The superficial branch of the femoral nerve provides innervation to it. It is a constituent of the pes anserinus.

The Sartorius Muscle: Anatomy and Function

The sartorius muscle is the longest strap muscle in the human body and is located in the anterior compartment of the thigh. It is the most superficial muscle in this region and has a unique origin and insertion. The muscle originates from the anterior superior iliac spine and inserts on the medial surface of the body of the tibia, anterior to the gracilis and semitendinosus muscles. The sartorius muscle is innervated by the femoral nerve (L2,3).

The primary action of the sartorius muscle is to flex the hip and knee, while also slightly abducting the thigh and rotating it laterally. It also assists with medial rotation of the tibia on the femur, which is important for movements such as crossing one leg over the other. The middle third of the muscle, along with its strong underlying fascia, forms the roof of the adductor canal. This canal contains important structures such as the femoral vessels, the saphenous nerve, and the nerve to vastus medialis.

In summary, the sartorius muscle is a unique muscle in the anterior compartment of the thigh that plays an important role in hip and knee flexion, thigh abduction, and lateral rotation. Its location and relationship to the adductor canal make it an important landmark for surgical procedures in the thigh region.

The correct nerve associated with loss of shoulder abduction due to denervation of the deltoid muscle in an elderly man with a proximal humerus fracture is the axillary nerve (C5,C6). Injury to the long thoracic, musculocutaneous, radial, and ulnar nerves are less likely based on the mechanism of injury and examination findings.

Upper limb anatomy is a common topic in examinations, and it is important to know certain facts about the nerves and muscles involved. The musculocutaneous nerve is responsible for elbow flexion and supination, and typically only injured as part of a brachial plexus injury. The axillary nerve controls shoulder abduction and can be damaged in cases of humeral neck fracture or dislocation, resulting in a flattened deltoid. The radial nerve is responsible for extension in the forearm, wrist, fingers, and thumb, and can be damaged in cases of humeral midshaft fracture, resulting in wrist drop. The median nerve controls the LOAF muscles and can be damaged in cases of carpal tunnel syndrome or elbow injury. The ulnar nerve controls wrist flexion and can be damaged in cases of medial epicondyle fracture, resulting in a claw hand. The long thoracic nerve controls the serratus anterior and can be damaged during sports or as a complication of mastectomy, resulting in a winged scapula. The brachial plexus can also be damaged, resulting in Erb-Duchenne palsy or Klumpke injury, which can cause the arm to hang by the side and be internally rotated or associated with Horner’s syndrome, respectively.

Due to the fact that the blood supply to the scaphoid enters from a small non-articular surface near its distal end, there is a risk of non-union with transverse fractures of the scaphoid.

The scaphoid bone has various articular surfaces for different bones in the wrist. It has a concave surface for the head of the capitate and a crescentic surface for the lunate. The proximal end has a wide convex surface for the radius, while the distal end has a tubercle that can be felt. The remaining articular surface faces laterally and is associated with the trapezium and trapezoid bones. The narrow strip between the radial and trapezial surfaces and the tubercle gives rise to the radial collateral carpal ligament. The tubercle also receives part of the flexor retinaculum and is the only part of the scaphoid bone that allows for the entry of blood vessels. However, this area is commonly fractured and can lead to avascular necrosis.

The wrist is classified as a synovial condyloid joint, consisting of 8 carpal bones that enable movements such as abduction, adduction, flexion, and extension. On the other hand, synovial hinge joints only allow movement in one plane, such as the elbow and knee joints. Meanwhile, secondary cartilaginous joints, also known as midline joints, are fibrocartilaginous fusions between two bones that allow very minimal movement, such as the sternomanubrial joint and symphysis pubis. Synovial saddle joints, on the other hand, allow flexion, extension, adduction, abduction, and circumduction, but not axial rotation, with examples including the carpometacarpal joint of the thumb and the sternoclavicular joint of the chest. Lastly, synovial plane joints only permit gliding movement, such as the joint between carpal bones in the hand.

Carpal Bones: The Wrist’s Building Blocks

The wrist is composed of eight carpal bones, which are arranged in two rows of four. These bones are convex from side to side posteriorly and concave anteriorly. The trapezium is located at the base of the first metacarpal bone, which is the base of the thumb. The scaphoid, lunate, and triquetrum bones do not have any tendons attached to them, but they are stabilized by ligaments.

In summary, the carpal bones are the building blocks of the wrist, and they play a crucial role in the wrist’s movement and stability. The trapezium bone is located at the base of the thumb, while the scaphoid, lunate, and triquetrum bones are stabilized by ligaments. Understanding the anatomy of the wrist is essential for diagnosing and treating wrist injuries and conditions.

Carpal Bones: The Wrist’s Building Blocks

The wrist is composed of eight carpal bones, which are arranged in two rows of four. These bones are convex from side to side posteriorly and concave anteriorly. The trapezium is located at the base of the first metacarpal bone, which is the base of the thumb. The scaphoid, lunate, and triquetrum bones do not have any tendons attached to them, but they are stabilized by ligaments.

In summary, the carpal bones are the building blocks of the wrist, and they play a crucial role in the wrist’s movement and stability. The trapezium bone is located at the base of the thumb, while the scaphoid, lunate, and triquetrum bones are stabilized by ligaments. Understanding the anatomy of the wrist is essential for diagnosing and treating wrist injuries and conditions.

The correct nerve that supplies the serratus anterior muscle is the long thoracic nerve. This muscle is responsible for pulling the scapula around the thorax, and damage to this nerve can cause medial winging of the scapula.

The axillary nerve is not the correct answer as it supplies the deltoid muscle, which is responsible for shoulder abduction. Damage to this nerve results in a flattened deltoid muscle, not winging of the scapula.

The musculocutaneous nerve supplies the biceps brachii muscle, which is responsible for elbow flexion. Damage to this nerve does not affect the scapulae.

The spinal accessory nerve supplies the sternocleidomastoid and trapezius muscles, and injury to this nerve may result in difficulty turning the head from side to side or shrugging the shoulders. It does not affect the scapulae.

Trauma to the thoracodorsal nerve may cause atrophy of the latissimus dorsi muscle and difficulty moving the affected shoulder, but it does not cause winging of the scapula.

Upper limb anatomy is a common topic in examinations, and it is important to know certain facts about the nerves and muscles involved. The musculocutaneous nerve is responsible for elbow flexion and supination, and typically only injured as part of a brachial plexus injury. The axillary nerve controls shoulder abduction and can be damaged in cases of humeral neck fracture or dislocation, resulting in a flattened deltoid. The radial nerve is responsible for extension in the forearm, wrist, fingers, and thumb, and can be damaged in cases of humeral midshaft fracture, resulting in wrist drop. The median nerve controls the LOAF muscles and can be damaged in cases of carpal tunnel syndrome or elbow injury. The ulnar nerve controls wrist flexion and can be damaged in cases of medial epicondyle fracture, resulting in a claw hand. The long thoracic nerve controls the serratus anterior and can be damaged during sports or as a complication of mastectomy, resulting in a winged scapula. The brachial plexus can also be damaged, resulting in Erb-Duchenne palsy or Klumpke injury, which can cause the arm to hang by the side and be internally rotated or associated with Horner’s syndrome, respectively.

After the primary infection (usually chickenpox during childhood), the herpes zoster virus remains inactive in the dorsal root or cranial nerve ganglia. The patient’s rash, which appears in the left T1 dermatome, indicates that the virus has been dormant in the T1 dorsal root ganglion. Although herpes zoster can reactivate at any time, it is more commonly associated with older age, recent viral infections, periods of stress, or immunosuppression.

Shingles is a painful blistering rash caused by reactivation of the varicella-zoster virus. It is more common in older individuals and those with immunosuppressive conditions. The diagnosis is usually clinical and management includes analgesia, antivirals, and reminding patients they are potentially infectious. Complications include post-herpetic neuralgia, herpes zoster ophthalmicus, and herpes zoster oticus. Antivirals should be used within 72 hours to reduce the incidence of post-herpetic neuralgia.

Hydralazine has the potential to cause drug-induced lupus, which is the most likely explanation for the patient’s symptoms. Lupus is characterized by respiratory symptoms, arthralgia, fatigue, and a malar rash (butterfly rash), and the patient has no prior history of these symptoms but has tested positive for anti-histone antibodies. Other drugs that can induce lupus include procainamide, isoniazid, and methyldopa.

Leukaemia, on the other hand, would present with abnormal full blood count results and a more gradual onset, making it less likely in this case.

Pneumonia and parvovirus B19 are also less likely causes, as the patient’s lack of fever and positive anti-histone antibodies do not align with these conditions.

Drug-induced lupus is a condition that differs from systemic lupus erythematosus in that it does not typically involve renal or nervous system complications. This condition can be resolved by discontinuing the medication that caused it. Symptoms of drug-induced lupus include joint and muscle pain, skin rashes (such as a malar rash), and pleurisy. Patients with this condition will test positive for ANA, but negative for dsDNA. Anti-histone antibodies are found in 80-90% of cases, while anti-Ro and anti-Smith are only present in around 5%. The most common causes of drug-induced lupus are procainamide and hydralazine, while less common causes include isoniazid, minocycline, and phenytoin.

When a disc herniates at the L5-S1 level, it can impact the L5 spinal nerve and result in a loss of sensation on the top of the foot. Additionally, it can affect the function of the sciatic nerve, leading to pain that travels down the leg from the lower back. This pain can be detected through the sciatic nerve stretch test.

If the disc herniation occurs at the L3-L4 level, it can cause a loss of sensation in the front of the thigh and knee. The femoral nerve stretch test would be positive in this case.

Finally, if the disc herniation is at the S1-S2 level, it can cause a loss of sensation on the back and side of the leg, as well as the outer edge of the foot.

Understanding Prolapsed Disc and its Features

A prolapsed disc in the lumbar region can cause leg pain and neurological deficits. The pain is usually more severe in the leg than in the back and worsens when sitting. The features of the prolapsed disc depend on the site of compression. For instance, compression of the L3 nerve root can cause sensory loss over the anterior thigh, weak quadriceps, reduced knee reflex, and a positive femoral stretch test. On the other hand, compression of the L4 nerve root can cause sensory loss in the anterior aspect of the knee, weak quadriceps, reduced knee reflex, and a positive femoral stretch test.

Similarly, compression of the L5 nerve root can cause sensory loss in the dorsum of the foot, weakness in foot and big toe dorsiflexion, intact reflexes, and a positive sciatic nerve stretch test. Lastly, compression of the S1 nerve root can cause sensory loss in the posterolateral aspect of the leg and lateral aspect of the foot, weakness in plantar flexion of the foot, reduced ankle reflex, and a positive sciatic nerve stretch test.

The management of prolapsed disc is similar to that of other musculoskeletal lower back pain, which includes analgesia, physiotherapy, and exercises. However, if the symptoms persist even after 4-6 weeks, referral for an MRI is appropriate. Understanding the features of prolapsed disc can help in early diagnosis and prompt management.

Stone formation is favored by the thick consistency of submandibular gland secretions. Additionally, the majority of stones are visible on radiographs. During gland removal surgery, the facial artery is typically tied off as it runs between the gland and mandible. The lingual artery may also be encountered later in the procedure when Wharton’s duct is being moved.

Anatomy of the Submandibular Gland

The submandibular gland is located beneath the mandible and is surrounded by the superficial platysma, deep fascia, and mandible. It is also in close proximity to various structures such as the submandibular lymph nodes, facial vein, marginal mandibular nerve, cervical branch of the facial nerve, deep facial artery, mylohyoid muscle, hyoglossus muscle, lingual nerve, submandibular ganglion, and hypoglossal nerve.

The submandibular duct, also known as Wharton’s duct, is responsible for draining saliva from the gland. It opens laterally to the lingual frenulum on the anterior floor of the mouth and is approximately 5 cm in length. The lingual nerve wraps around the duct, and as it passes forward, it crosses medial to the nerve to lie above it before crossing back, lateral to it, to reach a position below the nerve.

The submandibular gland receives sympathetic innervation from the superior cervical ganglion and parasympathetic innervation from the submandibular ganglion via the lingual nerve. Its arterial supply comes from a branch of the facial artery, which passes through the gland to groove its deep surface before emerging onto the face by passing between the gland and the mandible. The anterior facial vein provides venous drainage, and the gland’s lymphatic drainage goes to the deep cervical and jugular chains of nodes.