LEARNING OBJECTIVES
Enlist superficial and deep muscles of anterior and posterior fascial compartments of forearm•
Trace the course of nerves and arteries present in this region•
Enlist the boundaries of anatomical snuff box and bony landmarks in its floor•
Describe the attachments of, and structures passing deep to flexor and extensor retinacula in a sequential order•
Elucidate the anatomical basis of clinical presentation of compartment syndrome of forearm, Volkman’s ischemic contracture , rupture of various tendons and tennis elbow.
Identify the structures present in the models and prosected specimen of arm and forearm
The forearm is enclosed in a sheath of deep fascia, which
is attached to the periosteum of the posterior subcutaneous
border of the ulna. This fascial sheath , together with the interosseous membrane and fibrous intermuscular septa, divides the forearm into several
compartments, each having its own muscles, nerves, and
blood supply.
ANTERIOR COMPARTMENT
SUPERFICIAL VEINS
MUSCLES OF ANTERIOR COMPARTMENT
SUPEERFICIAL LAYER
Pronator Teres
Flexor Carpi Radialis
Palmaris Longus
Flexor Carpi Ulnaris
INTERMEDIATE LAYER
Flexor Digitorum Superficialis
DEEP LAYER MUSCLES
Flexor Pollicis Longus
Flexor digitorum profundus
Pronator quadratus
NERVES OF ANTERIOR COMPARTMENT
- Median
- Anterior interosseous
- Ulnar
MEDIAN NERVE
The median nerve leaves the cubital fossa by passing between the two heads of the pronator teres. It continues downward behind the flexor digitorum superficialis and rests posteriorly on the flexor digitorum
profundus. At the wrist, the median nerve emerges from the lateral border of the flexor digitorum superficialis
muscle and lies behind the tendon of the palmaris longus .
MEDIAN NERVE
Muscular branches in the cubital fossa to the pronator
teres, the flexor carpi radialis, the palmaris longus, and
the flexor digitorum superficialis (Fig. 9.22)
■■ Articular branches to the elbow joint
■■ Anterior interosseous nerve
■■ Palmar cutaneous branch. This arises in the lower part
of the forearm and is distributed to the skin over the
lateral part of the palm
BRANCHES
Muscular branches in the cubital fossa to the pronator teres, the flexor carpi radialis, the palmaris longus, and the flexor digitorum superficialis
Articular branches to the elbow joint
Anterior interosseous nerve
Palmar cutaneous branch.
This arises in the lower part of the forearm and is distributed to the skin over the lateral part of the palm.
ULNAR NERVE
The ulnar nerve passes from
behind the medial epicondyle of the humerus, crosses the medial ligament of the elbow joint, and enters the front of
the forearm by passing between the two heads of the flexor carpi ulnaris. It then runs down the forearm between the
flexor carpi ulnaris and the flexor digitorum profundus muscles. In the distal two thirds of the forearm, the ulnar artery lies on the lateral side of the ulnar nerve.At the wrist, the ulnar nerve becomes superficial and lies
between the tendons of the flexor carpi ulnaris and flexor digitorum superficialis muscles .The ulnar nerve enters the palm of the hand by passing in front of the flexor retinaculum and lateral to the pisiform bone;here, it has the ulnar artery lateral to it .
BRANCHES
ULNAR ARTERY
BRANCHES
Muscular branches to neighboring muscles
Recurrent branches that take part in the arterial anastomosis around the elbow joint
Branches that take part in the arterial anastomosis
around the wrist joint.
common interosseous artery:
which arises from the upper part of the ulnar artery and after a brief course divides into the anterior and posterior interosseous arteries. The interosseous arteries are distributed to the muscles lying in front of and behind the interosseous membrane; they provide nutrient arteries to the radius and ulna bone.
RADIAL ARTERY
Muscular branches to neighboring muscles
Recurrent branch, which takes part in the arterial anastomosis around the elbow joint
Superficial palmar branch, which arises just above the wrist, enters the palm of the hand, and frequently joins the ulnar artery to form the superficial palmar arch
