Radial Artery - Palmar and Dorsal Branches

• Arises near the lower border of the pronator quadratus.
• Runs medially, deep to the flexor tendons.
• Joins (anastomoses) the palmar carpal branch of the ulnar artery in front of the middle of the deep palmar arch.
• This forms a cruciform anastomosis.
• The palmar carpal arch supplies bones and joints at the wrist.

• Forms the dorsal carpal arch together with the branch of the ulnar artery.

• Arises just before the radial artery leaves the forearm.
• Winds backwards through the thenar muscles.
• Joins the terminal part of the ulnar artery to complete the superficial palmar arch (Fig. 9.29).

Ulnar Artery

Beginning, Course, and Termination

• The ulnar artery is the larger terminal branch of the brachial artery.
• It begins in the cubital fossa (Fig. 9.10).
• It runs obliquely downward and medially in the upper one-third of the forearm.
• In the lower two-thirds of the forearm, its course is vertical (Plate 9.7, Flowchart 9.2).
• It enters the palm by passing superficial to the flexor retinaculum.
• In the palm, it terminates by dividing into superficial and deep branches.
• Its distribution in the hand is described later.

Relations of the Ulnar Artery

• The artery is accompanied by venae comitantes.

Branches of the Ulnar Artery

• Both anastomose around the elbow.
• The anterior ulnar recurrent artery (smaller) runs upward and ends by anastomosing with the inferior ulnar collateral artery in front of the medial epicondyle.
• The posterior ulnar recurrent artery (larger) arises lower, ends by anastomosing with the superior ulnar collateral artery behind the medial epicondyle (see Fig. 8.11).

• Arises just below the radial tuberosity.
• Passes backward to reach the upper border of the interosseous membrane.
• Divides into the anterior and posterior interosseous arteries.

• The deepest artery on the front of the forearm.
• Accompanies the anterior interosseous nerve.
• Descends on the surface of the interosseous membrane between the flexor digitorum profundus and the flexor pollicis longus (Plate 9.7).
• Pierces the interosseous membrane at the upper border of the pronator quadratus to enter the extensor compartment.
• Gives muscular branches to the deep muscles of the front of the forearm, nutrient branches to the radius and ulna, and a median artery (which accompanies the median nerve).

• Near its origin, it gives off the interosseous recurrent artery, which runs upward.
• Ends by anastomosing with the middle collateral artery (posterior branch of the profunda brachii artery) behind the lateral epicondyle.
• Passes through a gap above the interosseous membrane to reach the back of the forearm (Fig. 8.10).

• Supply the medial muscles of the forearm.

• Both take part in the anastomoses around the wrist joint.
• The palmar carpal branch helps form the palmar carpal arch.
• The dorsal carpal branch arises just above the pisiform bone, winds backward deep to the tendons, and ends in the dorsal carpal arch.
• The dorsal carpal arch is formed medially by the dorsal carpal branch of the ulnar artery and laterally by the dorsal carpal branch of the radial artery.

DISSECTION NOTE

Relations of the Median Nerve

1. In the cubital fossa, the median nerve lies medial to the brachial artery, behind the bicipital aponeurosis, and in front of the brachialis.
2. The median nerve enters the forearm by passing between the two heads of the pronator teres. Here, it crosses the ulnar artery, from which it is separated by the deep head of the pronator teres (Fig. 9.10).
3. Along with the ulnar artery, the median nerve passes beneath the fibrous arch of the flexor digitorum superficialis, and runs deep to this muscle on the surface of the flexor digitorum profundus. It is accompanied by the median artery (a branch of the anterior interosseous artery). Near the flexor retinaculum (wrist), it lies between the tendons of the flexor digitorum superficialis (laterally) and the flexor digitorum superficialis (medially). It is overlapped by the palmaris longus.
4. The median nerve enters the palm by passing deep to the flexor retinaculum through the carpal tunnel.