human anantomy clinical q

Nerve Affected: Axillary

Difficulty abducting arm (deltoid weakness)

Nerve Affected: Suprascapular

Weak initiation of abduction and external rotation

Nerve Affected: Long Thoracic

"Winged scapula" from serratus anterior weakness

Nerve Affected: Spinal Accessory

Shoulder droop, weak shoulder shrug

Nerve Affected: Dorsal Scapular

Weak scapular retraction

Nerve Affected: Thoracodorsal

Weak shoulder extension/adduction (latissimus dorsi)

Latissimus dorsi Actions:

Shoulder extension

Adduction

Internal rotation

Latissimus dorsi Clinical associations:

Difficulty climbing, rowing, swimming, or performing pull-ups

Weakness after thoracic or axillary surgery

Thoracodorsal nerve injury

Used as a flap in reconstructive surgery

Trapezius Actions:

Upper fibers: elevation

Middle fibers: retraction

Lower fibers: depression/upward rotation

Trapezius Clinical associations:

Shoulder droop

Lateral scapular winging

Weak shrug

Difficulty abducting arm above 90°

Injury during posterior cervical lymph node biopsy

Rhomboid Major & Minor Actions:

Scapular retraction

Downward rotation

Rhomboid Major & Minor Clinical associations:

Rounded shoulder posture

Difficulty retracting scapula

Medial border scapular pain

Dorsal scapular neuropathy

Levator Scapulae Actions:

Scapular elevation

Ipsilateral neck side-bending

Levator Scapulae Clinical associations:

Common source of neck pain

Trigger points at superior angle of scapula

"Text neck" and desk-posture dysfunction

Serratus Posterior Muscles Actions:

Assists rib elevation

Serratus Posterior Muscles Clinical associations:

Rarely injured

May contribute to upper thoracic pain syndromes

Serratus Posterior Inferior Actions:

Assists rib depression

Serratus Posterior Inferior Clinical associations:

Chronic thoracolumbar pain

Frequently implicated in myofascial pain patterns

Quadratus Lumborum Actions:

Hip hike

Lateral trunk flexion

Lumbar stabilization

Quadratus Lumborum Clinical associations:

Common cause of unilateral low-back pain

Pain referral to sacroiliac region

Often tight in lumbar instability

Deltoid Actions:

Abduction (middle fibers)

Flexion (anterior)

Extension (posterior)

Deltoid Clinical associations:

Surgical neck fracture

Anterior shoulder dislocation

Loss of shoulder contour

Difficulty abducting beyond 15°

Serratus Anterior Actions:

Protraction

Upward rotation

Scapular stabilization

Serratus Anterior Clinical Associations:

Medial scapular winging

Difficulty with overhead activities

Long thoracic nerve injury

Pectoralis Major Action:

Adduction

Internal rotation

Flexion

Pectoralis Major Clinical Associations:

Tendon rupture during bench press

Loss of anterior axillary fold

Pectoralis Minor Actions:

Scapular protraction/depression

Pectoralis Minor Clinical Associations:

Thoracic outlet syndrome

Neurovascular compression beneath coracoid process

Teres Major Action:

Adduction

Internal rotation

Extension

Teres Major Clinical Associations:

Mimics latissimus dysfunction

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Injury in overhead athletes

supraspinatus action

Initiates abduction (0-15°)

Supraspinatus Clinical Associations:

Most common rotator cuff tear

Painful arc syndrome

Subacromial impingement

Infraspinatus Action:

External (lateral) rotation

Infraspinatus Clinical Associations:

Weak external rotation

Suprascapular nerve entrapment

Teres Minor actions:

External (lateral) rotation

Teres Minor Clinical Associations:

Quadrilateral space syndrome

Posterior shoulder pain

subscapularis actions

Internal (medial) rotation

Subscapularis clinical associations:

Positive lift-off test

Anterior shoulder instability

Suboccipital Actions:

Head extension

Rotation

Suboccipital clinical associations:

Cervicogenic headaches

Occipital pain

Upper cervical dysfunction

Splenius Capitis Actions:

Extension

Ipsilateral rotation

Splenius Capitis clinical associations:

Tension headaches

Whiplash injuries

Posterior neck pain

Splenius Cervicis Actions:

Extension

Ipsilateral rotation

Splenius Cervicis clinical associations:

Chronic neck stiffness

Postural dysfunction

Iliocostalis Actions:

Extension

Lateral flexion

Iliocostalis clinical associations:

Chronic lumbar strain

Low-back fatigue

Longissimus Actions:

Extension of spine and head

Longissimus clinical associations:

Thoracolumbar pain syndromes

Postural dysfunction

Spinalis actions:

Extension

Spinalis clinical associations:

Rarely isolated clinically

Usually involved with generalized extensor dysfunction

Multifidi action:

Segmental stabilization

Multifidi clinical associations:

One of the most studied muscles in chronic low-back pain

Atrophies after lumbar injury

Often targeted in rehabilitation

Rotatores action:

Proprioception

Fine rotational control

Rotatores clinical associations:

Rich in muscle spindles

Thought to contribute more to spinal position sense than force production

Semispinalis Capitis Actions:

Head extension

Contralateral rotation

Semispinalis Capitis clinical associations:

Tension-type headaches

Cervicogenic headaches

Frequently tender after whiplash

Condition: Herniated Disc

a condition where the inner gel like center of a spinal disc bulges out through a tear in the disc's outer layer, often causing pain and nerve issues.

Condition: Shoulder Dislocation

the head of the humerus is forced out of glenoid cavity. this can be anterior (most common) or posterior.

Condition: Rotator Cuff Tear

a tear in one or more of the tendons of the shoulders rotator cuff muscles, causing pain and weakness.

Condition: Frozen Shoulder

a painful condition where the shoulder becomes stiff and difficult to move, often following injury or immobilization.

Condition: Lordosis

an abnormal inward curvature of the lumbar spine, also known as swayback.

Condition: Impingement Syndrome

a condition where where shoulder movement cause the tendons to rub or catch on nearby tissues or ones, leading to pain.

Condition: Scoliosis

a lateral curvature of the spine which, which causes "S" and "c" shape on an xray.

Condition: Kyposis

a curve of the spine that appears as a hunchback or round back, often seen in the thoracic spine.

Condition: Winged Scapula

a condition where the shoulder blade protrudes outwards often due to damage or dysfunction of the serratus anterior muscle or long thoracic nerve.

A tennis player reports deep, aching pain in the shoulder that intensifies during follow-through of a serve. Strength is decreased with external rotation and abduction. MRI reveals no obvious tear. What structure is most likely involved?

Infraspinatus

External rotation and pain with overhead movements suggest overuse or strain of the ___________ muscle.

infraspinatus

A patient recovering from a shoulder dislocation complains of difficulty performing horizontal adduction and flexion of the arm. Weakness is noted with pressing motions, but no signs of rotator cuff involvement are present. Which nerve is most likely affected?

lateral pectoral nerve

This nerve innervates the ____________, which is involved in ___________ _______, horizontal adduction, and ________ _________. Injury to the _____ ______ nerve results in weakness with pushing motions (e.g., bench press, pushing open doors) without rotator cuff involvement.

pectoralis major, shoulder flexion, and internal rotation, lateral pectoral.

A patient complains of difficulty maintaining good posture and reports a "pinching" feeling between the shoulder blades when carrying a backpack. On exam, the medial border of the scapula is slightly lifted from the thorax, and retraction is weak. Which nerve is most likely involved?

dorsal scapular nerve

dorsal scapular nerve Innervates

the rhomboids and levator scapulae. Damage leads to weak scapular retraction and medial border winging, especially noticeable when carrying loads.

A rowing athlete presents with weakness in shoulder extension and internal rotation. Atrophy is noted in the posterior axillary region, and the inferior border of the scapula appears less prominent. Which nerve is most likely impaired?

Thoracodorsal nerve

Thoracodorsal nerve Innervates

the latissimus dorsi. Weakness in shoulder extension and internal rotation with posterior axillary fold atrophy indicates injury to this nerve.

A volleyball player shows medial scapular winging during resisted shoulder flexion. Her scapula lifts away from the thoracic wall, especially with overhead movements. Which nerve is likely involved?

Long thoracic nerve

Long thoracic nerve causes

Scapular winging during a wall push-up test or arm elevation suggests injury to the serratus anterior, innervated by the long thoracic nerve.

A patient complains of difficulty initiating shoulder abduction and external rotation. There is no pain, but significant atrophy is noted in the supraspinous and infraspinous fossae. Reflexes and sensation are intact. What is the most likely cause?

Compression of the suprascapular nerve at the suprascapular notch

Compression of the suprascapular nerve at the suprascapular notch

The supraspinatus and infraspinatus are both affected, leading to weakness in abduction and external rotation, with visible atrophy and no sensory deficit.