Question

A patient presents with a weak grip. He does not have any history of injury to his upper limb. While this could be a local problem following an injury to the upper limb, it could just as easily be damage to the spinal nerve resulting from an injury to his neck, causing pressure on one or more roots of the brachial plexus. The weakness may not be muscle weakness (such as from disuse), but lack of innervation to the hand; these present similarly. Your task will be to understand the anatomy of this region and possible sources of impairment that present similarly. With a good understanding of anatomy, the correct source can be identified.

Answer 1

Answer :

The ulnar nerve may getting impairement.

Ulnar nerve supply muscles (grip).

The ulnar nerve innervates the flexor muscles of the forearm including the flexor carpiulnaris and flexor digitorum profundus.It also innervates the intrinsic muscles of the hand including the pulmaris brevis, lumbricals, hypothenar and interossei muscles.

Ulnar nerve route :

• The unlar nerve is a major peripheral nerve of the upper limb.
• The ulnar nerve arises from the brachiel plexus. It is a continuation of the medial cord, containing fibers from spinal roots C8 and T1.
• After arising from the brachial plexus , the ulnar nerve descends down the medial aspect of the upper arm. At the elbow it passes posterior to the medial epicondyle of the humerus and gives rise to an articular branch that supplies the elbow joint. The ulnar nerve is palpable and vulnerable to injury at the medial epicondyle.
• The ulnar nerve innervates muscles in the anterior of the forearm, and in the hand.

Flexor carpi ulnaris -flexus and adducts the hand at the wrist.

Flexor digitorum profundus - flexes the ring and little fingers at the distal interphalengeal joint.

Ulnar-brachial plexus roots :

• The brachial plexus is a network of nerve fibers that supplies the skin and musculature of the upper limb. It begis in the route of the neck, passes through the axilla, and runs through the entire upper extrimity.
• The plexus is formed by anterior rami (devisions) of cervical spinal nerves C5, C6, C7 and C8, and the first thorasic spinal nerve, T1

Roots :

• The roots refer the anterior of the spinal nerves that comprise the brachial plexus. These are the anterior rami of spinal nerves C5, C6, C7, C8, and T1.
• At each vertebral level, paired spinal nerves arise. They leave the spinal cord via the intervertebral foramina of the vertebral column.
• Each spinal nerves then devides into an anteriour and posteriour ramus.
• The roots of the brachial plexus are formed by the anterior rami of spinal nerves C5-T1 ( the posterior divisions innervate the skin and musculature of the intrinsic back muscles.)
• After their formation, these nerve pass betweeen the anterior and midial scalene muscles to enter the base of the neck.

The brachial plexus begins as the anterior rami of five spinal nerve roots C5-T1, which emerge from the intervertebral foramen of their respective vertebrae to lie in the posterior triangle of the neck between the anterior and medial scalene muscles.