Systems Anatomy

By admin On Jun 28, 2023

Ovid: Hand and Wrist

Authors: Doyle, James R.

Title: Hand and Wrist, 1st Edition

> Table of Contents > Section I – Basic Anatomy > 1 – Anatomy > 1.2 – Systems Anatomy

1.2

Systems Anatomy

The following figures and discussion represent and are
designed to provide an overall perspective on the deeper anatomy—the
skeletal, muscular, vascular, and neural anatomy—of the upper
extremity. The perspective spans from the shoulder and neck for
discussions of the skeletal, neural, and vascular anatomy, and from the
elbow for the muscular system.

Skeletal Anatomy

The osseous structures of the upper limb include the
humerus, the radius and ulna, eight carpal bones, five metacarpals, and
14 phalanges. The upper extremity skeleton is depicted in Figure 1.2-1.

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Figure 1.2-5
Schematic illustration of the brachial plexus, associated major
branches, peripheral branches and muscles they innervate. A, nerve to
subclavius; B, lateral pectoral nerve; C, subscapular nerve; D,
thoracodorsal nerve; E, medial antebrachial cutaneous nerve; F, medial
brachial cutaneous nerve; G, medial pectoral nerve.

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Figure 1.3-1 Currently accepted terminology and depiction of movement in the forearm, wrist, fingers: wrist, forearm (A), thumb (B).

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Table 1.3-1 Anatomic Basis for Movement in the Upper Extremity

Joint/Motion	Muscle	Nerve	Root
Elbow
Flexion	Brachialis	Musculocutaneous	C5+C6+C7
	Biceps	Musculocutaneous	C5+C6
Extension	Triceps	Radial	C6+C7+C8
Forearm
Supination	Biceps	Musculocutaneous	C5+C6
	Supinator	Radial	C7+C8
Pronation	Pronator teres	Median	C6+C7
	Pronator quadratus	Anterior interosseous branch of median	C7+C8
Forearm
Flexion	Flexor carpi radialis	Median	C6+C7
	Flexor carpi ulnaris	Ulnar	C7+C8+T1
Extension	Extensor carpi radialis longus	Radial	C6+C7
	Extensor carpi radialis brevis	Radial	C7+C8
	Extensor carpi ulnaris	Radial	C7+C8
Finger MCP
Flexion	Medial two lumbricals	Ulnar	C8+T1
	Lateral two lumbricals	Median	C8+T1
Extension	Extensor digitorum communis, extensor indicis, extensor digiti minimi	Posterior interosseous of radial	C7+C8
Abduction	Dorsal interossei*	Ulnar	C8+T1
	Abductor digiti minimi	Ulnar	C8+T1
Adduction	Palmar interossei*	Ulnar	C8+T1
Finger PIP
Flexion	Flexor digitorum superficialis	Median	C8+T1
Extension	Extensor digitorum communis, extensor indicis, extensor digiti minimi	Posterior interosseous of radial	C7+C8
Finger DIP
Flexion	Flexor digitorum profundus	Ulnar; anterior interosseous of median	C8+T1
Extension	Extensor digitorum communis, extensor indicis, extensor digiti minimi	Posterior interosseous of radial	C7+C8
Thumb
Palmar abduction	Abductor pollicis longus	Radial	C7+C8
	Abductor pollicis brevis	Median	C8+T1
Dorsal adduction	Adductor pollicis	Ulnar	C8+T1
Thumb MCP
Flexion	Flexor pollicis brevis deep head	Ulnar	C8+T1
	Flexor pollicis brevis superficial head	Median	C8+T1
Extension	Extensor pollicis brevis	Radial	C7+C8
Thumb IP
Flexion	Flexor pollicis longus	Median	C7+C8
Extension	Extensor pollicis longus	Radial	C7+C8
DIP, distal interphalangeal; IP, interphalangeal; MCP, metacarpophalangeal; PIP, proximal interphalangeal. * The dorsal and palmar interossei are abductors and adductors, respectively, of the fingers. They also flex the MCP joints and extend the PIP and DIP joints. These so-called intrinsic muscles are the balancing and mediating forces between the powerful extrinsic flexors and extensors of the fingers. Loss of the intrinsic muscles results in significant deformity in the hand and the reader is referred to the Doyle/Botte reference in Suggested Reading, pages 581–595 and chapter 13 of this text for a comprehensive discussion of the anatomy and function of these muscles.

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Muscular Anatomy

The muscles of the forearm are depicted in Figure 1.2-2 and the hand in Figure 1.2-3.

Vascular Anatomy

The vascular anatomy from the axillary artery to the hand is depicted in Figure 1.2-4.

Neural Anatomy

The brachial plexus, median, ulnar, and radial nerves and the muscles they innervate are depicted in Figure 1.2-5.