Hand and Upper limb Anatomy related to hand transplantation

It describes hand and upper limb anatomy pertaining to hand transplantation. It is very helpful for people involved in hand transplantation procedure. It also contains Inclusion, Exclusion criteria. Technical Steps to Hand transplantation.

1. Hand Anatomy

2. Superficial Flexors

3. Deep Flexors

4. Anatomical Course The median nerve is derived from the medial and lateral cords of the brachial plexus. It contains fibres from roots C6-T1 and can contain fibres from C5 in some individuals. After originating from the brachial plexus in the axilla, the median nerve descends down the arm, initially lateral to the brachial artery. Halfway down the arm, the nerve crosses over the brachial artery, and becomes situated medially. The median nerve enters the anterior compartment of the forearm via the cubital fossa. In the forearm, the nerve travels between the flexor digitorum profundus and flexor digitorum superficialis muscles. The median nerve gives off two major branches in the forearm: Anterior interosseous nerve – supplies the deep muscles in the anterior forearm. Palmar cutaneous nerve – innervates the skin of the lateral palm. (The functions of these nerves are explored in more detail later in the article). After giving off the anterior interosseous and palmar cutaneous branches, the median nerve enters the hand via the carpal tunnel – where it terminates by dividing into two branches: Recurrent branch – innervates the thenar muscles. Palmar digital branch – innervates the palmar surface and fingertips of the lateral three and half digits. Also innervates the lateral two lumbrical muscles.

5. Anatomical Course The ulnar nerve arises from the brachial plexus within the axilla region. It is a continuation of the medial cord and contains fibres from spinal roots C8 and T1. After arising from the brachial plexus, the ulnar nerve descends in a plane between the axillary artery (lateral) and the axillary vein (medial). It proceeds down the medial aspect of the arm with the brachial artery located lateral. At the mid-point of the arm, the ulnar nerve penetrates the medial fascial septum to enter the posterior compartment of the arm. It passes posterior to the elbow through the ulnar tunnel (small space between the medial epicondyle and olecranon). Here, it also gives arise to an articular branch which supplies the elbow joint. In the forearm, the ulnar nerve pierces the two heads of the flexor carpi ulnaris, and travels deep to the muscle, alongside the ulna. Three main branches arise in the forearm: Muscular branch – innervates two muscles in the anterior compartment of the forearm. Palmar cutaneous branch – innervates the medial half of the palm. Dorsal cutaneous branch – innervates the dorsal surface of the medial one and a half fingers, and the associated dorsal hand area. At the wrist, the ulnar nerve travels superficially to the flexor retinaculum, and is medial to the ulnar artery. It enters the hand via the ulnar canal (Guyon’s canal). In the hand, the nerve terminates by giving rise to superficial and deep branches

6. Anatomical Course The radial nerve is the terminal continuation of the posterior cord of the brachial plexus. It therefore contains fibres from nerve roots C5 – T1. The nerve arises in the axilla region, where it is situated posteriorly to the axillary artery. It exits the axilla inferiorly (via the triangular interval), and supplies branches to the long and lateral heads of the triceps brachii. The radial nerve then descends down the arm, travelling in a shallow depression within the surface of the humerus, known as the radial groove. As it descends, the radial nerve wraps around the humerus laterally, and supplies a branch to the medial head of the triceps brachii. During much of its course within the arm, it is accompanied by the deep branch of the brachial artery. To enter the forearm, the radial nerve travels anterior to the lateral epicondyle of the humerus, through the cubital fossa. The nerve then terminates by dividing into two branches: Deep branch (motor) – innervates the muscles in the posterior compartment of the forearm. Superficial branch (sensory) – contributes to the cutaneous innervation of the dorsal hand and fingers.

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