Anatomy UWORLD

Prepatellar bursitis

A bursa is a fluid-filled synovial sac that serves to alleviate pressure from bony prominences and reduce friction between muscles and tendons. Acute trauma or chronic repetitive pressure can cause injury, leading to localized pain and tenderness. Prepatellar bursitis causes anterior knee pain and is usually due to repetitive or prolonged kneeling

Distal biceps tendon rupture

A distal biceps tendon rupture characteristically occurs in older patients after forceful extension of the elbow while the biceps muscle is contracted, resulting in a visible mass in the mid-upper arm (ie, "Popeye" deformity)

Pudendal nerve

Branches of the pudendal nerve innervate the external urethral and anal sphincters. They also provide sensory innervation of the external genitalia.

Subacromial bursitis (vs tendinitis)

Bursitis tends to cause pain both during movement and at rest (e.g. simply laying on your shoulder is painful), while tendonitis only causes pain while you are actively using the muscle of the inflamed tendon. This expands on @doomarion's comment! Note for both, though, that you can have point tenderness since you are actively putting pressure where there is inflammation

Fracture of orbital floor

Fractures to the orbital floor commonly result from direct frontal trauma to the orbit. The infraorbital nerve runs along the orbital floor in a groove in the maxilla before exiting the skull just inferior to the orbit. Damage can result in paresthesia of the upper cheek, upper lip, and upper gingiva. In addition, the inferior rectus muscle can also become entrapped, limiting vertical gaze

Basilar skull fractures

Hematomas over the mastoid process (Battle sign), along with periorbital ecchymosis and clear otorrhea, are signs of basilar skull fractures

Deltoid muscle

Injury to the axillary nerve most commonly occurs in the setting of shoulder trauma (eg, anterior dislocation, humeral fracture) and presents with sensory loss over the lateral shoulder and weakness on shoulder abduction (due to denervation of the deltoid muscle)

Radial head subluxation

Nursemaid's elbow The annular ligament encircles the radial head and holds it and the ulna together. In children, ligamental laxity can predispose to radial head subluxation (ie, nursemaid elbow) when axial traction is applied to the arm

Anosmia

Olfactory signals are relayed via the olfactory nerve (CN I) through the cribriform plate to the olfactory bulb, which then projects to the primary olfactory cortex in the medial temporal lobe. Head trauma can tear olfactory nerve (CNI) rootlets as they cross the cribriform plate, causing anosmia. Anosmia is often interpreted by patients as loss of taste

Pterion fracture

Pterion= a region where the frontal, parietal, temporal, and sphenoid bones meet in the skull. The bone is thin in this region, and fractures there risk lacerating the middle meningeal artery and causing an epidural hematoma. Epidural hematomas require prompt treatment as they are under systemic arterial pressure and can expand rapidly, leading to elevated intracranial pressure (can cause Cushing reflex), brain herniation (eg, uncal herniation with oculomotor nerve palsy), and death. The middle meningeal artery is a branch of the maxillary artery (one of the terminal branches of the external carotid artery), which enters the skull at the foramen spinosum and supplies the dura mater and periosteum

Pudendal nerve injury

Pudendal nerve injury can occur due to excessive stress on the pelvic floor during labor and delivery (eg, prolonged second stage). Nerve injury leads to denervation and weakness of the perineal musculature (eg, external anal sphincter), which can present as new-onset fecal incontinence and decreased anal sphincter tone on digital anorectal examination. Because perianal skin sensation is compromised, patients also have loss of the anal wink reflex. decreased penile sensation or external urethral sphincter paralysis

Midline episiotomy

The perineal body is a fibromuscular tissue between the urogenital and anal triangle. A midline episiotomy is a vertical incision from the posterior vaginal opening to the perineal body. It transects the vaginal submucosal tissue but not the external anal sphincter or the rectal mucosa.

Rotator cuff tear

Rotator cuff tears may occur during shoulder dislocation but do not cause nerve injury. The rotator cuff is made up of the subscapularis, supraspinatus, infraspinatus, and teres minor muscles/tendons

Temporal bone fractures

Significant head trauma can produce fracture lines through the temporal bone that may affect the facial nerve (by direct transection or causes swelling and distention)

Spenoid bone fracture

Sphenoid bone fractures are associated with damage to the optic nerve (CN II), pituitary gland injury, and leakage of CSF into the sphenoid sinus

What can lead to impairment of corneal reflex?

The corneal reflex involves cranial nerves V1 (sensory) and VII (motor) and processing in the pons. It can be impaired by trauma to the superior orbital fissure but not fractures to the orbital floor

Temporal bone fractures: what can it damage?

The facial nerve (cranial nerve VII) controls the motor function of the face and can be impaired in fractures of the temporal bone after lateral head trauma or zygomatic orbit fractures

Appendectomy commonly injures which nerve?

The iliohypogastric nerve arises from the L1 nerve root, emerges from the lateral border of the upper psoas major, and passes behind the kidney anterior to the quadratus lumborum. The nerve provides motor function to the anterolateral abdominal wall muscles. Its anterior branch emerges above the superficial inguinal ring to innervate the skin above the pubic region; the lateral branch descends over the iliac crest to innervate the gluteal region. Injury to the anterior branch during appendectomy causes decreased sensation at the suprapubic region

Injury to the interosseous membrane

The interosseous membrane is a broad sheet of connective tissue between the radius and ulna that provides forearm stability and a point of attachment for the forearm muscles. Injury to the membrane is associated with fracture of the radius or ulna after a fall onto an outstretched hand.

Latissimus dorsi

The latissimus dorsi is a large thoracolumbar muscle that originates from the iliac crest and lumbar fascia to the spinous processes of T7-12 and lower ribs, and inserts at the bicipital groove of the humerus. It is innervated by the thoracodorsal nerve. Primary functions include extension, adduction, and medial (internal) rotation of the humerus

Lingual nerve

The lingual nerve is a branch of the mandibular division of the trigeminal nerve (CN V3) that provides somatic sensation to the anterior two-thirds of the tongue. Fibers of the chorda tympani nerve, a branch of the facial nerve (CN VII), also travel with the lingual nerve to relay taste from the anterior two-thirds of the tongue.If taste disturbances were due to injury of the lingual nerve, tongue numbness would also be present

Osteonecrosis of femoral head

The medial femoral circumflex artery and its branches provide the majority of the blood supply to the femoral head and neck. Injury to these vessels due to a displaced femoral neck fracture can cause osteonecrosis of the femoral head.

Musculocutaneous nerve

The musculocutaneous nerve innervates the major forearm flexors (eg, biceps brachii, brachialis) and coracobrachialis (flexes and adducts the arm) and provides sensory innervation to the lateral forearm. It is derived from the upper trunk of the brachial plexus (C5-C7) and can be injured by trauma or strenuous upper extremity exercise

Radical prostatectomy and damage to the nerves surrounding the prostate

The prostatic plexus lies within the fascia of the prostate and originates from the inferior hypogastric plexus. The cavernous nerves carry post-ganglionic PNS fibers that facilitate penile erection.Prostatectomy or injury to the prostatic plexus can cause erectile dysfunction *Although urethral muscle injury can occur during prostate surgery, injury to the main pudendal nerve is less common with prostatectomy

How to locate appendix during surgery

The teniae coli, three longitudinal smooth muscle bands on the surface of the cecum and colon, converge where the appendix arises from the cecum. Therefore, the teniae coli can be used as guidance to locate the appendix during surgery

Injury to the ulnar collateral ligament

The ulnar (medial) collateral ligament is typically injured by intense, repetitive overuse involving a valgus stress at the elbow (eg, pitching a baseball), resulting in medial elbow pain that increases during throwing motions

Why might there be diplopia when looking up with fracture of orbital floor?

UW QID# 11742 had the same question. Fracture of the orbital floor causes displacement of the orbital contents through the floor and can cause enophthalmos and entrapment of the IR muscle (diplopia when looking up). Also, damage to the infraorbital nerve (a branch of V2), which exits through the infraorbital foramen, will cause numbness of the upper cheek, upper lip, and upper gingiva

Suprapatellar bursa

above the patella

Flattening of the deltoid muscle with acromial prominence after a shoulder injury suggests what?

an anterior humerus dislocation. This injury most commonly results from a blow to an externally rotated and abducted arm. There is often associated axillary nerve injury, resulting in deltoid paralysis and loss of sensation over the lateral shoulder

Fibrous flexor sheaths

are thick tunnels on the palmar surface of the fingers that act like pulleys to allow the flexor digitorum profundus tendons to flex the fingers at the interphalangeal joints Swelling of the tendon and/or fibrous sheath can result in painful catching or locking of the affected finger during flexion (ie, trigger finger)

Injury to the radial (lateral) collateral ligament of the elbow

can occur with acute varus stress during a fall onto an outstretched hand and is often associated with fracture or dislocation of the elbow

coracobrachialis

flexes and adducts the arm

Pineal gland (in back)

it is in the back