What is a Truss?

Key Assumptions (Ideal Truss)

• All joints are frictionless pins
• Loads are applied only at joints
• Members are straight and weightless
• Members carry axial forces only (no shear, no bending)

Common Types

Analysis Methods

1. Method of Joints - Resolve forces at each joint using equilibrium (ΣFx = 0, ΣFy = 0)
2. Method of Sections - Cut through the truss and apply equilibrium to an isolated portion; useful when only a few member forces are needed
3. Graphical Method (Maxwell Diagram) - Older graphical technique

Determinacy

m + r = 2j

• m = number of members
• r = number of reactions
• j = number of joints
• If m + r < 2j → mechanism (unstable)
• If m + r > 2j → statically indeterminate

Applications

• Bridges - Railway bridges (Pratt, Warren), highway spans
• Roof structures - Residential and industrial roof trusses (Fink, Howe)
• Towers - Transmission towers, communication masts
• Space frames - 3D trusses for large roofs (stadiums, airports)
• Cranes and gantries

Materials

• Steel - Most common for large structures (high strength-to-weight ratio)
• Timber - Traditional roof trusses
• Aluminum - Lightweight applications (aircraft, temporary structures)
• Reinforced concrete - Rare, but used in some roof systems

Truss in Hernia

Historical Background

• Fischer's Mastery of Surgery, 8th ed.

How It Works

1. The hernia contents (bowel/omentum) are first reduced (pushed back into the abdomen)
2. The truss is then strapped on so the pad presses firmly over the hernial defect (the hole in the abdominal wall)
3. This creates a mechanical barrier that prevents the contents from re-protruding when the patient coughs, strains, or increases intra-abdominal pressure

Types of Hernia for Which It Is Used

Current Clinical Indications (Limited)

"A truss should be used only temporarily to prevent recurrent protrusion before surgery can be arranged."

• Pfenninger and Fowler's Procedures for Primary Care, 3rd ed.

"A truss can be used to control a hernia but nowadays few surgeons recommend this approach."

• Bailey and Love's Short Practice of Surgery, 28th ed.

Complications and Drawbacks of Prolonged Truss Use

"With prolonged usage, atrophy of the spermatic cord has been reported and eventual surgical repair is made more difficult due to fibrosis of the tissues."

• Mulholland and Greenfield's Surgery, 7th ed.

"If the patient is using a truss for a long time, discoloration and streaks of brown pigmentation due to deposition of haemosiderin may be seen. The subcutaneous tissue may be atrophied, so the skin may be wrinkled."

• S Das: A Manual on Clinical Surgery, 13th ed.

Key Rule Before Applying a Truss

Why Surgery is Preferred Over a Truss

• Truss does not cure the hernia - the fascial defect remains
• Hernia tends to continue enlarging despite truss use
• Up to 70% crossover to surgery within 10 years even in watchful-waiting patients
• Modern hernia repair has a recurrence rate of <2% and is safe as a day-case procedure
• Insufficient evidence that trusses are as effective as surgery for symptom control

Summary

Pectineal Fascia and Its Surrounding Anatomy

1. The Pectineus Muscle - Foundation

"Pectineus spans between the superior ramus of pubis and pectineal line of the femur. It adducts and flexes hip joint."

• Fischer's Mastery of Surgery, 8th ed.

2. The Pectineal (Cooper's) Ligament - Key Derivative

"The pectineus muscle covers the floor of the vascular gap and inserts into the pectineal line, a ridge of bone, via the pectineal or Cooper's ligament."

• Sabiston Textbook of Surgery

"Cooper's (pectineal) ligament is the lateral portion of the lacunar ligament that is fused to the periosteum of the pubic tubercle."

• Schwartz's Principles of Surgery, 11th ed.

3. The Femoral Triangle - Key Regional Structure

• N - Femoral Nerve
• A - Femoral Artery
• V - Femoral Vein
• E - Empty space (femoral canal)
• L - Lymphatics

4. The Femoral Canal and Femoral Ring - Critical Relations

"The femoral ring is bounded anteriorly by the inguinal ligament, posteriorly by the pectineus muscle and its fascia, medially by the lacunar ligament, and laterally by the femoral vein."

• Gray's Anatomy for Students

5. The Iliopectineal Arch - Dividing the Gap Below the Inguinal Ligament

"The gap below the inguinal ligament is divided into two spaces by another condensation of the iliopsoas fascia, known as the ilio-pectineal arch. The medial aspect is vascular, and the lateral is muscular."

• Sabiston Textbook of Surgery

6. The Lacunar Ligament - Medial Neighbor

"The fibrous band that curves downward from the medial attachment of the inguinal ligament is called the lacunar ligament, which extends further medially as the pectineal ligament (Cooper's ligament) and runs along the superior pubic ramus. This sharp-edged ligament defines the medial boundary of the vascular compartment (femoral ring) and may entrap the hernial sac in patients with a femoral hernia."

• Thieme Atlas of Anatomy: General Anatomy and Musculoskeletal System

7. The Iliopectineal Bursa - Clinically Important

8. Summary - Structures Surrounding the Pectineal Fascia

            Inguinal Ligament (superior)
                      |
    Femoral Artery | Femoral Vein | [Femoral Canal]
                      |
        PECTINEAL FASCIA (posterior floor of femoral ring)
                      |
            Pectineus Muscle
                      |
            Pectineal Line of Femur
                      |
            Cooper's (Pectineal) Ligament

Medial: Lacunar ligament → Cooper's ligament
Lateral: Iliopsoas fascia (covering iliopsoas + femoral nerve)
Superficial roof: Fascia lata → Cribriform fascia → Skin

Surgical Relevance

• The pectineal fascia forms the posterior wall of the femoral ring - so femoral hernias lie directly anterior to it
• Cooper's ligament repair (McVay repair) sutures the inguinal structures to the pectineal ligament, using this structure as a firm anchor
• The aberrant obturator artery (enlarged pubic branch of inferior epigastric) may course along the lacunar ligament - if cut during femoral hernia repair, it causes severe bleeding (the "corona mortis" variant)
• The iliopsoas fascia over the lateral compartment must be kept intact to protect the femoral nerve during laparoscopic repair

Henry's Procedure (Anterior/Volar Approach to the Radius)

"The length of the radius can be approached from either the volar-based approach described by Henry or by a dorsal-based approach..."

• Rockwood and Green's Fractures in Adults, 10th ed.

Indications

• Fractures of the radial shaft (diaphysis) - particularly the distal 4/5ths
• Both-bone forearm fractures (radius + ulna)
• Radial osteotomy / corrective osteotomy for malunion
• Removal of hardware / implants along the radius
• Tumour excision involving the radial shaft
• Volar plating of distal radius fractures (modified Henry approach)

"The volar approach of Henry is used in nearly all fractures of the radius."

• Campbell's Operative Orthopaedics, 15th ed. 2026

Patient Positioning

• Patient supine
• Arm extended on a hand table, forearm supinated
• Tourniquet applied to the upper arm

Skin Incision

• Proximally: lateral aspect of the biceps tendon (at the antecubital fossa)
• Distally: radial styloid

The Internervous Plane (KEY Concept)

"The approach proceeds through a true internervous interval since the brachioradialis is innervated by the radial nerve and both PT and FCR are innervated by the median nerve."

• Rockwood and Green's Fractures in Adults, 10th ed.

Step-by-Step Surgical Technique

1. Superficial Dissection

• Incise skin and fascia
• Identify the interval between brachioradialis (lateral) and PT/FCR (medial)
• The radial artery runs under brachioradialis in the proximal/middle third, then surfaces between FCR and brachioradialis distally
• To retract the radial artery medially: ligate the vascular branches (leash of Henry) - small branches from the radial artery to the brachioradialis
• The superficial branch of the radial nerve (SBRN) runs under brachioradialis and must be retracted laterally with the brachioradialis

2. Deep Dissection - Varies by Fracture Level

"From distal to proximal, the radial shaft is covered by pronator quadratus, flexor digitorum superficialis, pronator teres, and supinator. Note that to gain proximal access to the radius, the recurrent radial artery has to be ligated."

• Rockwood and Green's Fractures in Adults

The "Leash of Henry"

"Isolate and ligate the leash of Henry (radial artery branches) proximally and strip the supinator from its insertion subperiosteally."

• Miller's Review of Orthopaedics, 9th ed.

Critical Structures at Risk

"Retraction around the radial neck should be avoided to prevent injury to the PIN."

• Rockwood and Green's Fractures, 10th ed.

Comparison: Henry vs. Thompson Approach

Modified Henry Approach

"Modified Henry volar approach to elbow joint: Fascia incised to expose brachioradialis laterally and biceps/brachialis medially. Lacertus fibrosus divided. Dissection deepened between biceps tendon and pronator teres medially and brachioradialis laterally."

• Campbell's Operative Orthopaedics, 15th ed. 2026

Summary

Henry's Operation for Femoral Hernia

Historical Context

Classification of Approaches to Femoral Hernia

"A third type of femoral hernia repair is the preperitoneal repair. Access to the preperitoneal space is gained through an abdominal incision or laparoscopy. This approach is particularly useful during repair of a strangulated hernia since there is more space to allow for inspection of the bowel."

• Mulholland and Greenfield's Surgery, 7th ed.

Indications for Henry's (Cheatle-Henry) Operation

• Strangulated femoral hernia - primary indication; best approach for bowel viability assessment and resection if needed
• Incarcerated femoral hernia - difficult to reduce from below
• Large femoral hernia sac with voluminous intra-abdominal contents
• Bilateral femoral hernias - single incision can address both sides
• Recurrent femoral hernia (avoids scar tissue from previous anterior repair)
• Suspected aberrant obturator artery (corona mortis) - safer from above

"If the femoral hernia sac is large and filled with voluminous intra-abdominal contents, a preperitoneal repair should be considered... This approach is particularly useful during repair of a strangulated hernia since there is more space to allow for inspection of the bowel to ensure viability."

• Maingot's Abdominal Operations

Surgical Technique - Step by Step

Position

• Patient supine
• Head-down (Trendelenburg) tilt helps displace bowel away from the operative field

Incision

• Vertical midline incision below the umbilicus, extending to the pubic symphysis (or a lower transverse/Pfannenstiel-style incision)
• Alternatively, a paramedian incision lateral to the rectus abdominis

Entry into Preperitoneal Space

1. Skin and subcutaneous tissue divided
2. Anterior rectus sheath incised
3. Rectus abdominis retracted medially (not divided)
4. Dissection carried deep to the rectus into the preperitoneal (extraperitoneal) space
5. The peritoneum is NOT opened (extraperitoneal dissection) - it is gently swept upward and away
6. The space of Retzius (retropubic preperitoneal space) is developed by blunt dissection

Identification and Reduction of Hernia

1. The preperitoneal fat is dissected to expose the posterior surface of the inguinal region and the femoral ring
2. The femoral hernia sac is identified protruding through the femoral ring (bounded anteriorly by the inguinal ligament, posteriorly by pectineal fascia/Cooper's ligament, medially by lacunar ligament, laterally by femoral vein)
3. The sac is drawn upward (reduced from above) into the preperitoneal space
4. If strangulated: the sac is opened, bowel viability assessed; ischaemic bowel resected and anastomosed in the preperitoneal space before full reduction
5. The neck of the sac is transfixed and ligated; the sac excised

Repair of the Defect

1. The femoral canal defect is closed:

• Suture repair: Cooper's (pectineal) ligament is sutured to the inguinal ligament/iliopubic tract - narrows the femoral ring
• Mesh repair: A preperitoneal mesh is placed to cover the entire myopectineal orifice - preferred in modern practice

Wound Closure

1. The preperitoneal space is allowed to collapse
2. Rectus sheath closed, then skin

Key Anatomical Relationships Encountered

Advantages of Henry's Operation

• Provides the widest exposure of the femoral ring from inside
• Allows bowel inspection and resection without a separate laparotomy incision
• Can address bilateral hernias through the same midline incision
• Preperitoneal mesh placement here covers the entire myopectineal orifice - prevents recurrence of both inguinal and femoral hernias
• Avoids operating through scar tissue in recurrent cases
• Safe control of the aberrant obturator artery

Disadvantages / Risks

• More invasive than the low (crural) approach for elective simple hernias
• Risk of peritoneal entry - converts to intraperitoneal operation
• Learning curve for preperitoneal anatomy
• Recurrent femoral hernia if defect not fully covered

Modern Equivalent

"Cheatle-Henry operation is a safe and secure technique to operate on femoral hernia... With laparoscopic surgery, total extraperitoneal technique is done with a patch to cover the femoral ring."

• Cervantes-Castro et al., Cirugía y Cirujanos 2011 (PMID: 22380991)

Summary