Monday test syllabus 1. Hip bone Femur bone features and attachment 2. Knee joint with clinicals 3. Hip joint with clinicals 4. Thigh front compartment 5. Thigh medial compartment 6. Thigh posterior compartment 7. Gluteal region 8. Femoral triangle 9. Adductor canal 10. Femoral nerve 11. Obturator nerve 12. Trochanteric anastomosis 13. Cruciate anastomosis Mbbs 1st year anatomy learning objectives for test Explain each one of it
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Here are your complete MBBS 1st Year Anatomy study notes for Monday's test, sourced from Gray's Anatomy for Students.
MBBS 1st Year Anatomy - Monday Test Study Notes
1. Hip Bone & Femur - Features and Attachments
Hip Bone (Os Coxae)
The hip bone is formed by three bones fused together: ilium (superior), ischium (posteroinferior), and pubis (anteroinferior). They fuse at the acetabulum - the cup-shaped socket for the femoral head.
Key features:
- Ilium: iliac crest (ASIS, AIIS, PSIS, PIIS), iliac fossa, gluteal lines (anterior, posterior, inferior), greater sciatic notch, arcuate line
- Ischium: ischial tuberosity (hamstring origin), ischial spine (lesser sciatic notch), ischiopubic ramus
- Pubis: pubic crest, pubic tubercle, pectineal line (pecten pubis), obturator foramen
Key attachments on hip bone:
| Structure | Attachment Site |
|---|---|
| Sartorius | ASIS |
| Rectus femoris (straight head) | AIIS |
| Inguinal ligament | ASIS → pubic tubercle |
| Hamstrings (biceps long head, semitendinosus) | Ischial tuberosity |
| Adductor magnus (ischial part) | Ischial tuberosity |
| Gracilis | Ischiopubic ramus |
| Adductor longus/brevis | Body of pubis |
| Piriformis | Anterior sacrum, inner surface of ilium |
| Gluteus maximus | Posterior ilium (behind posterior gluteal line) |
| Gluteus medius | Between anterior and posterior gluteal lines |
| Gluteus minimus | Between anterior and inferior gluteal lines |
Femur - Features and Attachments
The femur is the longest and strongest bone in the body. It has an oblique course from the neck (lateral) to the distal shaft (medial), placing the knee under the body's center of gravity.
Proximal end:
- Head: spherical, covered by hyaline cartilage except the fovea capitis (attachment of ligament of head of femur; carries branch of obturator artery)
- Neck: connects head to shaft at angle of ~125-135° (angle of inclination). Anteverted ~10-15°
- Greater trochanter: lateral projection - attachment of gluteus medius (lateral facet), gluteus minimus (anterolateral facet), obturator internus + gemelli (medial side)
- Lesser trochanter: posteromedial - insertion of iliopsoas (psoas major + iliacus)
- Intertrochanteric line (anterior): iliofemoral ligament attaches; vastus lateralis and medialis origins
- Intertrochanteric crest (posterior): quadratus femoris inserts at quadrate tubercle
- Trochanteric fossa: medial aspect of greater trochanter, deep - obturator externus inserts here
Shaft:
- Linea aspera: rough posterior ridge with medial and lateral lips. Key attachment landmark
- Medial lip: vastus medialis, adductor longus, adductor magnus
- Lateral lip: vastus lateralis, biceps femoris (short head), gluteus maximus (gluteal tuberosity superiorly)
- Pectineal line: proximal shaft, posterior - pectineus inserts
- Gluteal tuberosity: superior lateral lip of linea aspera - gluteus maximus inserts
Distal end:
- Medial and lateral condyles: articulate with tibia
- Intercondylar fossa (posterior): cruciate ligament attachments (ACL - lateral condyle; PCL - medial condyle)
- Adductor tubercle: on medial condyle, superior aspect - adductor magnus (ischial head) inserts
- Epicondyles: medial (tibial collateral ligament) and lateral (fibular collateral ligament)
- Patellar surface (anterior): V-shaped trench, lateral side larger and steeper
2. Knee Joint - With Clinicals
Type
Largest synovial joint in the body. Composite joint with two articulations:
- Tibiofemoral - weight-bearing hinge joint
- Patellofemoral - allows quadriceps pull over the knee without tendon wear
Articular Surfaces
- Medial and lateral femoral condyles (curved in flexion, flat in extension)
- Superior surfaces of tibial condyles
- Posterior surface of patella + patellar surface of femur
Menisci
Two fibrocartilaginous C-shaped structures between femoral and tibial condyles:
- Medial meniscus: larger, C-shaped, firmly attached to joint capsule and tibial collateral ligament - less mobile, more commonly injured
- Lateral meniscus: smaller, more circular, not attached to capsule (connected to popliteus tendon) - more mobile
- Connected anteriorly by the transverse ligament of the knee
- Function: improve congruency, absorb shock, deepen joint socket
Ligaments
| Ligament | Attachment | Function |
|---|---|---|
| Tibial (medial) collateral | Medial femoral epicondyle → medial tibia | Resists valgus (abduction) stress |
| Fibular (lateral) collateral | Lateral femoral epicondyle → head of fibula | Resists varus (adduction) stress |
| Anterior cruciate (ACL) | Anterior intercondylar area of tibia → posterior part of medial surface of lateral femoral condyle | Prevents anterior tibial displacement; taut in extension |
| Posterior cruciate (PCL) | Posterior intercondylar area of tibia → anterior part of lateral surface of medial femoral condyle | Prevents posterior tibial displacement; taut in flexion |
| Patellar ligament | Apex of patella → tibial tuberosity | Transmits quadriceps force |
| Oblique popliteal ligament | Extension of semimembranosus tendon | Reinforces posterior capsule |
Locking Mechanism
In full extension, the femur medially rotates on the tibia (or tibia laterally rotates), producing "locking." This is due to the larger medial femoral condyle. Popliteus muscle "unlocks" the knee by laterally rotating the femur (or medially rotating the tibia) to initiate flexion.
Blood Supply
Genicular anastomosis (from femoral, popliteal, and anterior tibial arteries).
Nerve Supply
- Femoral nerve (anterior capsule)
- Obturator nerve (medial capsule)
- Tibial nerve (posterior capsule)
- Common fibular nerve (lateral capsule) Hilton's law: nerves supplying a joint also supply muscles moving the joint and skin over them.
Clinicals
Meniscal Injury:
- Caused by forceful rotation/twisting of the knee
- Types: vertical, horizontal, bucket-handle tears
- Medial meniscus torn more commonly (less mobile)
- Symptoms: joint-line pain, locking/clicking, giving way, delayed swelling
- Investigation: MRI (gold standard)
- Treatment: arthroscopic repair or partial meniscectomy
ACL Injury:
- Common in sports (pivoting, landing)
- Immediate swelling (haemarthrosis), positive Lachman test, anterior drawer test
- MRI confirms; often requires surgical reconstruction
PCL Injury:
- Posterior drawer test positive
- "Dashboard injury" mechanism
Collateral Ligament Injury:
- MCL: valgus stress (medial pain)
- LCL: varus stress (lateral pain)
- MRI for assessment
Unhappy Triad (O'Donoghue):
- Valgus force injury: ACL + MCL + medial meniscus torn together
Bursae around knee:
- Prepatellar bursa (housemaid's knee - inflammation from kneeling)
- Infrapatellar bursa (clergyman's knee)
- Semimembranosus bursa (Baker's cyst in popliteal fossa)
Anterolateral ligament (ALL):
Recently described structure from lateral femoral epicondyle to anterolateral tibia; may control internal tibial rotation.
3. Hip Joint - With Clinicals
Type
Multiaxial ball and socket synovial joint. Designed for stability and weight-bearing at the expense of mobility.
Movements: Flexion, extension, abduction, adduction, medial rotation, lateral rotation, circumduction.
Articular Surfaces
- Spherical head of femur (covered by hyaline cartilage except fovea)
- Lunate surface of acetabulum (covered by hyaline cartilage; broadest superiorly)
- Acetabular labrum: fibrocartilaginous collar deepening the socket; bridges the acetabular notch as the transverse acetabular ligament, converting the notch to a foramen
Ligaments of Hip Joint
| Ligament | Attachment | Notes |
|---|---|---|
| Iliofemoral (Y-ligament of Bigelow) | AIIS and acetabular rim → intertrochanteric line | Strongest ligament in the body; limits extension and lateral rotation |
| Pubofemoral | Obturator crest of pubis → lower intertrochanteric line | Limits abduction and extension |
| Ischiofemoral | Ischial part of acetabulum → greater trochanter (spirals over posterior capsule) | Limits extension and medial rotation |
| Ligament of head of femur (ligamentum teres) | Fovea capitis → acetabular fossa + transverse acetabular ligament | Contains branch of obturator artery to femoral head; not important mechanically |
Joint Stability
The deep socket (acetabulum covers >50% of femoral head), acetabular labrum, strong capsule and ligaments, and surrounding musculature all contribute to stability.
Blood Supply to Femoral Head
- Medial circumflex femoral artery (branch of profunda femoris) - most important; runs posterior, enters via retinacular vessels
- Lateral circumflex femoral artery - minor contribution
- Artery in ligamentum teres (branch of obturator artery) - minor, may be obliterated in adults
Nerve Supply
Femoral, obturator, superior gluteal, and nerve to quadratus femoris.
Clinicals
Avascular Necrosis (AVN) of femoral head:
- Blood supply disrupted after neck of femur fracture (intracapsular), dislocation, or long-term steroid use/alcohol
- Fracture close to head (subcapital) most dangerous - disrupts retinacular vessels
- Results in collapse of femoral head
- Investigation: MRI earliest; X-ray shows crescent sign, collapse later
Neck of Femur Fracture:
- Intracapsular (subcapital/transcervical): risk of AVN and non-union; may need hemiarthroplasty or total hip replacement
- Extracapsular (intertrochanteric/subtrochanteric): blood supply relatively preserved; treat with dynamic hip screw (DHS)
- Common in elderly osteoporotic women after low-energy falls
- Limb: shortened, adducted, externally rotated
Dislocation of Hip:
- Posterior dislocation (most common): knee/dashboard injury; limb flexed, adducted, internally rotated; sciatic nerve at risk
- Anterior dislocation: limb abducted, externally rotated; femoral nerve/vessels at risk
Congenital Hip Dislocation (DDH):
- Barlow (dislocates) and Ortolani (reduces) tests in neonates
- Shallow acetabulum - treated with Pavlik harness or surgery if late
Piriformis Syndrome:
- Sciatic nerve compressed by piriformis muscle
- Buttock pain radiating down leg
Trendelenburg Sign:
- Weakness of gluteus medius/minimus on stance side → pelvis drops to opposite side
- Positive in superior gluteal nerve injury, fracture neck of femur, congenital hip dislocation
4. Thigh - Anterior Compartment
Contents
Muscles, femoral nerve (L2-L4), femoral artery and vein.
Muscles (Table 6.3, Gray's)
| Muscle | Origin | Insertion | Nerve | Action |
|---|---|---|---|---|
| Psoas major | T12-L5 vertebral bodies, IVDs, transverse processes | Lesser trochanter | Ant. rami L1-L3 | Flexes hip |
| Iliacus | Iliac fossa | Lesser trochanter | Femoral N. (L2,L3) | Flexes hip |
| Rectus femoris | AIIS (straight head), ilium above acetabulum (reflected head) | Quadriceps tendon → patella → tibial tuberosity | Femoral N. (L2,L3,L4) | Flexes hip; extends knee |
| Vastus lateralis | Lateral intertrochanteric line, greater trochanter, lateral linea aspera | Quadriceps tendon, lateral patella | Femoral N. (L2,L3,L4) | Extends knee |
| Vastus medialis | Medial intertrochanteric line, pectineal line, medial linea aspera | Quadriceps tendon, medial patella | Femoral N. (L2,L3,L4) | Extends knee; last 15° extension (VMO) |
| Vastus intermedius | Upper 2/3 anterior and lateral femoral shaft | Quadriceps tendon | Femoral N. (L2,L3,L4) | Extends knee |
| Sartorius | ASIS | Medial tibia (pes anserinus) | Femoral N. (L2,L3) | Flexes hip + knee; abducts + laterally rotates thigh |
Quadriceps femoris = rectus femoris + 3 vasti. Insert via quadriceps tendon → patella → patellar ligament → tibial tuberosity.
Pes Anserinus ("goose foot"): combined insertion of sartorius + gracilis + semitendinosus onto medial tibia.
Arteries
- Femoral artery (continuation of external iliac artery below inguinal ligament)
- Profunda femoris (deep artery of thigh) - main supply to thigh muscles
- Lateral circumflex femoral artery - supplies anterior/lateral thigh; forms trochanteric anastomosis
Clinical - Compartment Syndrome
Elevated pressure within the anterior compartment compromises capillary flow → neuromuscular damage. Causes: limb trauma, haemorrhage. Treatment: emergency fasciotomy.
5. Thigh - Medial Compartment (Adductor Compartment)
Muscles
| Muscle | Origin | Insertion | Nerve | Action |
|---|---|---|---|---|
| Gracilis | Ischiopubic ramus (outer surface) | Medial tibia (pes anserinus) | Obturator N. (L2,L3) | Adducts hip; flexes knee |
| Pectineus | Pectineal line (pecten pubis) | Pectineal line of femur (proximal shaft) | Femoral + Obturator N. (L2,L3) | Adducts + flexes hip |
| Adductor longus | Body of pubis (below pubic crest) | Middle 1/3 of linea aspera | Obturator N. (L2,L3,L4) | Adducts hip |
| Adductor brevis | Body and inferior ramus of pubis | Pectineal line and upper linea aspera | Obturator N. (L2,L3,L4) | Adducts hip |
| Adductor magnus | Ischiopubic ramus (adductor part) + ischial tuberosity (hamstring/ischial part) | Linea aspera + adductor tubercle (ischial part) | Obturator N. (adductor part); Sciatic N./tibial (ischial part) | Adducts hip (adductor part); extends hip (ischial part) |
| Obturator externus | Margins of obturator foramen, obturator membrane | Trochanteric fossa of femur | Obturator N. (L3,L4) | Laterally rotates hip |
Adductor hiatus: gap in the adductor magnus tendon near its adductor tubercle insertion; femoral vessels pass through to become popliteal vessels.
Nerve Supply
Obturator nerve supplies all except: pectineus (femoral N.) and ischial part of adductor magnus (sciatic N.).
6. Thigh - Posterior Compartment (Hamstrings)
Muscles
| Muscle | Origin | Insertion | Nerve | Action |
|---|---|---|---|---|
| Biceps femoris (long head) | Inferomedial ischial tuberosity | Head of fibula | Tibial division, sciatic N. (L5,S1,S2) | Flexes knee; extends and laterally rotates hip |
| Biceps femoris (short head) | Lateral lip of linea aspera | Head of fibula | Common fibular division, sciatic N. | Flexes knee; laterally rotates leg |
| Semitendinosus | Inferomedial ischial tuberosity (with biceps long head) | Medial tibia (pes anserinus) | Tibial division, sciatic N. (L5,S1,S2) | Flexes knee; extends hip; medially rotates thigh + leg |
| Semimembranosus | Superolateral ischial tuberosity | Groove on medial tibial condyle (oblique popliteal ligament, popliteus fascia) | Tibial division, sciatic N. (L5,S1,S2) | Flexes knee; extends hip; medially rotates leg |
All hamstrings originate from the ischial tuberosity and are innervated by the sciatic nerve (tibial division, except short head of biceps = common fibular division).
Important: The ischial part of adductor magnus is functionally a "hamstring" - innervated by sciatic nerve, extends hip.
Clinical - Hamstring Injuries
Common in sprinters and field athletes. Can range from muscle strain to complete avulsion. In adolescents, ischial apophysis avulsion is typical due to sudden hip flexion. MRI is the investigation of choice.
7. Gluteal Region
Overview
Lies posterolateral to the bony pelvis and proximal femur. Communicates with pelvic cavity through greater and lesser sciatic foramina.
Muscles - Two Groups
Deep group (lateral rotators):
| Muscle | Origin | Insertion | Nerve | Action |
|---|---|---|---|---|
| Piriformis | Anterior sacrum (S2-S4) | Superior border of greater trochanter (medial side) | S1, S2 | Laterally rotates extended hip; abducts flexed hip |
| Obturator internus | Deep surface of obturator membrane, anterolateral pelvic wall | Medial surface of greater trochanter | Nerve to OI (L5,S1) | Laterally rotates extended hip; abducts flexed hip |
| Gemellus superior | External surface of ischial spine | With obturator internus tendon → greater trochanter | Nerve to OI (L5,S1) | Same as obturator internus |
| Gemellus inferior | Upper ischial tuberosity | With obturator internus tendon → greater trochanter | Nerve to QF (L5,S1) | Same as obturator internus |
| Quadratus femoris | Lateral ischium (anterior to ischial tuberosity) | Quadrate tubercle, intertrochanteric crest | Nerve to QF (L5,S1) | Laterally rotates hip |
Superficial group:
| Muscle | Origin | Insertion | Nerve | Action |
|---|---|---|---|---|
| Gluteus maximus | Posterior ilium, dorsal sacrum, coccyx, sacrotuberous ligament | Iliotibial tract (75%) + gluteal tuberosity (25%) | Inferior gluteal N. (L5,S1,S2) | Powerful hip extension; lateral rotation; stabilises knee via ITB |
| Gluteus medius | Between anterior and posterior gluteal lines | Lateral surface of greater trochanter | Superior gluteal N. (L4,L5,S1) | Abducts hip; prevents pelvic drop in walking; medially rotates thigh |
| Gluteus minimus | Between anterior and inferior gluteal lines | Anterolateral facet of greater trochanter | Superior gluteal N. (L4,L5,S1) | Same as gluteus medius |
| Tensor fasciae latae | ASIS, outer iliac crest | Iliotibial tract → lateral tibial condyle (Gerdy's tubercle) | Superior gluteal N. (L4,L5) | Stabilises knee in extension; abducts hip |
Nerves in the Gluteal Region
- Sciatic nerve (L4-S3): largest nerve in body; exits through greater sciatic foramen below piriformis; descends between deep and superficial groups into posterior thigh
- Superior gluteal nerve (L4,L5,S1): exits through greater sciatic foramen above piriformis; supplies gluteus medius, minimus, TFL
- Inferior gluteal nerve (L5,S1,S2): exits through greater sciatic foramen below piriformis; supplies gluteus maximus
- Posterior cutaneous nerve of thigh (S1-S3): exits below piriformis; sensory to posterior thigh, buttock, and perineum
- Pudendal nerve + internal pudendal vessels: exits through greater sciatic foramen, then re-enters through lesser sciatic foramen to reach perineum
- Nerve to obturator internus (L5,S1): similar course to pudendal nerve
Clinical
- Trendelenburg gait: superior gluteal nerve damage → gluteus medius weakness → pelvis drops to unsupported side during single-leg stance. Trunk lurches to affected side to compensate.
- Sciatic nerve injury in gluteal region: foot drop, loss of hamstring power, sensory loss in leg and foot. Caused by posterior hip dislocation, misplaced IM injection (inject in upper outer quadrant to avoid sciatic nerve), piriformis syndrome.
8. Femoral Triangle
Boundaries (Mnemonic: "SAIL")
| Boundary | Structure |
|---|---|
| Base (superior) | Inguinal ligament |
| Medial border | Medial margin of adductor longus |
| Lateral border | Medial margin of sartorius |
| Floor (deep) | Iliopsoas (lateral) + pectineus (medial) + adductor longus (deepest medial) |
| Roof (superficial) | Fascia lata + cribriform fascia |
| Apex | Where sartorius and adductor longus meet (continuous with adductor canal) |
Contents (Lateral to Medial: NAVEL)
- N - Femoral Nerve (most lateral; NOT in femoral sheath)
- A - Femoral Artery
- V - Femoral Vein
- E - Empty space (lymphatics)
- L - Lymphatics (femoral canal - most medial compartment of femoral sheath)
The femoral nerve is outside the femoral sheath; artery, vein, and lymphatics are inside.
Femoral Sheath
Funnel-shaped sleeve of fascia (transversalis + iliac fascia) enclosing:
- Lateral compartment: femoral artery
- Middle compartment: femoral vein
- Medial compartment: femoral canal (lymphatics; potential site of femoral hernia)
Femoral Hernia
Bowel or omentum protrudes through the femoral canal. More common in women (wider pelvis). Appears below and lateral to the pubic tubercle (inguinal hernia is above and medial). Treated surgically; risk of strangulation.
Femoral Pulse
Palpable just below the inguinal ligament, midway between the ASIS and pubic symphysis (mid-inguinal point).
9. Adductor Canal (Hunter's Canal / Subsartorial Canal)
Location
Fascial tunnel in the middle third of the thigh, deep to sartorius muscle. Extends from the apex of the femoral triangle (superiorly) to the adductor hiatus in adductor magnus (inferiorly), where contents emerge into the popliteal fossa.
Boundaries
| Wall | Structure |
|---|---|
| Anterior (roof) | Sartorius muscle + vastoaddductor membrane (fibrous sheet) |
| Posteromedial | Adductor longus (upper part), adductor magnus (lower part) |
| Posterolateral | Vastus medialis |
Contents
- Femoral artery - continues as popliteal artery after passing through adductor hiatus
- Femoral vein - runs posterior to artery in the canal
- Saphenous nerve (branch of femoral N.) - continues beyond the hiatus as the saphenous nerve (does not pass through adductor hiatus; exits via the fascial roof)
- Nerve to vastus medialis - passes through upper part of canal
- Descending genicular artery - branch of femoral artery within the canal
Clinical Significance
- Adductor canal block: regional anaesthesia for knee surgery (blocks saphenous nerve, preserves motor function of quadriceps better than femoral nerve block)
- The femoral artery is accessible here for angiography/angioplasty
- Hunter's canal aneurysm: superficial femoral artery pseudoaneurysm may occur here
10. Femoral Nerve
Origin
From the posterior divisions of the anterior rami of L2, L3, L4 (lumbar plexus)
Course
- Forms in the substance of psoas major
- Emerges lateral to psoas, descends between psoas and iliacus (in iliac fossa)
- Passes under the inguinal ligament into the femoral triangle, lateral to the femoral artery
- NOT inside the femoral sheath (lies lateral to it)
- Divides into anterior and posterior divisions just below the inguinal ligament
Branches
In the abdomen:
- Branches to iliacus and psoas major
In the femoral triangle (anterior division):
- Muscular: nerve to pectineus, sartorius
- Cutaneous: medial and intermediate cutaneous nerves of thigh (anterior thigh skin)
In the femoral triangle (posterior division):
- Muscular: nerves to quadriceps femoris (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius)
- Saphenous nerve: largest and longest cutaneous branch; descends through adductor canal; supplies skin on medial side of leg and medial side of foot
Motor Supply
- All muscles of the anterior compartment of thigh
- Iliacus and pectineus (in the abdomen/at inguinal level)
Sensory Supply
- Anterior thigh, anteromedial knee, medial leg, medial foot (via saphenous nerve)
Clinical - Femoral Nerve Injury
- Psoas abscess / haematoma: can compress the nerve in the iliac fossa
- Inguinal hernial repair: injury possible
- Femoral nerve palsy: loss of knee extension (quadriceps), loss of hip flexion (partially), loss of knee jerk reflex, sensory loss over anterior thigh and medial leg
11. Obturator Nerve
Origin
From the anterior divisions of the anterior rami of L2, L3, L4 (lumbar plexus)
Course
- Descends in the psoas muscle and emerges from its medial border
- Crosses the pelvic brim and descends on the lateral wall of the pelvis
- Passes through the obturator canal (with obturator vessels) to enter the medial compartment of the thigh
- Divides in the obturator canal into anterior and posterior divisions
Branches
Anterior division (descends anterior to adductor brevis):
- Muscular: adductor longus, adductor brevis, gracilis, pectineus (sometimes)
- Cutaneous: skin over upper medial aspect of thigh
- Articular: hip joint (anterior)
Posterior division (descends posterior to adductor brevis):
- Muscular: obturator externus, adductor magnus (adductor part), adductor brevis (sometimes)
- Articular: knee joint (posterior capsule via descending branch)
Motor Supply
All medial compartment muscles except:
- Pectineus = femoral nerve (mainly)
- Ischial part of adductor magnus = sciatic nerve (tibial division)
Sensory Supply
Upper medial thigh
Clinical - Obturator Nerve Injury
- Obstetric injury: nerve damaged on the lateral pelvic wall during difficult/assisted delivery
- Symptoms: weakness of thigh adductors, sensory deficit on medial thigh
- Obturator hernia: bowel protrudes through obturator canal; can compress the nerve causing medial thigh/knee pain (Howship-Romberg sign)
- Pain from hip joint can be referred to the medial knee via the articular branch (clinically important)
12. Trochanteric Anastomosis
Definition
An arterial anastomotic network around the greater trochanter and upper femur, supplying the hip region and femoral head.
Vessels Contributing
| Artery | Source |
|---|---|
| Ascending branch of lateral circumflex femoral artery | Profunda femoris (deep artery of thigh) |
| Ascending branch of medial circumflex femoral artery | Profunda femoris (passes to trochanteric fossa) |
| Inferior gluteal artery | Internal iliac artery (via greater sciatic foramen below piriformis) |
| Superior gluteal artery | Internal iliac artery (via greater sciatic foramen above piriformis) |
Significance
- Provides collateral circulation around the hip joint
- The medial circumflex femoral artery is the most important contributor to femoral head blood supply via the retinacular vessels (ascending cervical arteries)
- After an intracapsular neck of femur fracture, this anastomosis may sustain some blood supply but is often insufficient to prevent AVN
13. Cruciate Anastomosis
Definition
A cross-shaped arterial anastomosis at the level of the lesser trochanter on the posterior aspect of the upper thigh, connecting the gluteal vessels above with the perforating arteries below.
Vessels Contributing
| Artery | Division |
|---|---|
| Inferior gluteal artery (descending branch) | Internal iliac (descends from above) |
| Medial circumflex femoral artery (transverse branch) | Profunda femoris (runs medially) |
| Lateral circumflex femoral artery (transverse branch) | Profunda femoris (runs laterally) |
| First perforating artery (ascending branch) | Profunda femoris (ascends from below) |
The four vessels form a "cross" or cruciform arrangement at the level of the lesser trochanter.
Significance
- Important collateral circulation around the hip: if the femoral artery is ligated above the profunda femoris origin, blood can still reach the lower limb via this anastomosis
- Connects the gluteal circulation (internal iliac) with the thigh circulation (external iliac via femoral)
- Clinically relevant in aortoiliac occlusion and femoral artery ligation
Quick Revision Summary Table
| Topic | Key Nerve | Key Artery | Key Action/Clinical |
|---|---|---|---|
| Anterior thigh | Femoral N. (L2-L4) | Femoral A. / Profunda | Knee extension (quads) |
| Medial thigh | Obturator N. (L2-L4) | Obturator A. | Hip adduction |
| Posterior thigh | Sciatic N. (L4-S3) | Perforating arteries | Hip extension, knee flexion |
| Gluteal region | Sup/Inf gluteal N. | Sup/Inf gluteal A. | Hip extension, abduction |
| Hip joint | Femoral/Obturator/Sciatic | Med. circumflex femoral | AVN risk in intracapsular #NOF |
| Knee joint | Femoral/Obturator/Sciatic/Fibular | Genicular anastomosis | Meniscal/cruciate tears |
Source: Gray's Anatomy for Students (9780323934237)
Good luck on Monday! Focus especially on the muscle tables (origins, insertions, innervations), the clinical correlates (AVN, Trendelenburg, meniscal injury, femoral hernia), and the anastomosis components for short/long answer questions.
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