System: Musculoskeletal

Gemellus Inferior

Gemellus Inferior The structure indicated is the gemellus inferior muscle. The gemellus inferior muscle is one of the muscles of the gluteal region. The muscles in the gluteal region are divided into a superficial and deep group. There are four muscles of the superficial group: Gluteus maximus Gluteus medius Gluteus minimus Tensor fasciae latae There are 5 muscles in the deep group: Gemellus superior Gemellus inferior Quadratus femoris Piriformis Obturator internus The word gemellus comes from the Latin “gemelli” which means “twins”. There are therefore two gemelli muscles, the gemellus superior, and the gemellus inferior. The gemelli muscles are located …

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gemellus inferior

Superior Extensor Retinaculum

Superior Extensor Retinaculum The structure indicated is the superior extensor retinaculum of the leg. Retinacula (retinaculum singular) are bands of connective tissue which surround tendons and hold them in place. They function to stabilise tendons as the muscles to which they attach contract to cause movement. There are retinacula in the wrist, ankle and knee. In the ankle, there is the flexor retinaculum, the peroneal retinacula and on the extensor surface, there is the superior and inferior extensor retinacula. The superior retinaculum is situated distally in the leg just above the ankle joint, attaching to the anterior aspects of the …

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superior extensor retinaculum

Flexor Carpi Radialis

Flexor Carpi Radialis The structure indicated is the flexor carpi radialis muscle. The flexor carpi radialis is one of four muscles in the superficial layer of muscles in the anterior compartment of the forearm. The anterior compartment of the forearm consists of three layers of muscles: Superficial layer Intermediate layer Deep layer Four muscles are located in the superficial layer (from lateral to medial): Flexor carpi ulnaris Palmaris longus Flexor carpi radialis Pronator teres All four muscles of the superficial layer have a common origin on the medial epicondyle of the humerus. Origin: Medial epicondyle of humerus Insertion: Bases of …

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flexor carpi radialis

Latissimus Dorsi

Latissimus Dorsi The structure indicated is the latissimus dorsi muscle. The latissimus dorsi muscle is one of the superficial muscles of the back. There are three groups of back mucsles: Superficial Intermediate Deep The superficial group of back muscles consists of 5 muscles: Trapezius Latissimus dorsi Levator scapulae Rhomboid major Rhomboid minor “Latissimus dorsi” translates literally from the Latin has the “broadest muscle of the back”, which reflects its large, flat structure. The latissimus dorsi muscle is involved in several movements of the upper limbs as well as movement at the lumbar spine and it also plays a role as …

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latissimus dorsi

Lateral Pterygoid

Lateral Pterygoid The structure indicated is the lateral pterygoid muscle. The lateral pterygoid muscle is one of four muscles of mastication: Masseter Temporalis Medial pterygoid Lateral pterygoid The muscles of mastication act on the temporomandibular joint (TMJ), which is the joint of the jaw formed between the mandible and temporal bone. The TMJ is a synovial joint, which differs in structure to other synovial joints in that it contains a fibrocartilagenous articular disc that divides the joint into two parts. The two joint compartments result in different movements at the TMJ. The lower joint compartment allows rotational movement, whilst the …

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lateral pterygoid

Flexor Hallucis Brevis

Flexor Hallucis Brevis The structure indicated is the flexor hallucis brevis muscle of the foot. The intrinsic muscles on the plantar aspect of the foot are divided into four layers. The flexor hallucis brevis muscle is located in the third layer of intrinsic foot muscles. There are three muscles located in this layer: Flexor hallucis brevis Adductor hallucis Flexor digiti minimi brevis The flexor hallucis brevis muscle splits into two parts which insert onto the medial and lateral aspects of the base of the first phalanx of the great toe. Origin: Plantar surface of cuboid and lateral cuneiform bone Insertion: Lateral and medial sides of …

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flexor hallucis brevis

Superior Angle of Scapula

Superior Angle of Scapula The superior angle of the scapula is indicated in the diagram. The scapula is a bone that connects the humerus with the clavicle. The scapula consists of two surfaces: Costal Posterior The scapula has three borders: Superior Medial Lateral The scapula has three angles: Superior Inferior Lateral The superior angle of the scapula is covered by the trapezius muscle. It is formed at the point where the medial and lateral borders meet and provides attachment for the levator scapulae muscle and omohyoid muscle. Learn more about the anatomy of the scapula in this tutorial
superior angle of scapula

Radial Fossa

Radial Fossa The structure indicated is the radial fossa of the distal humerus. The distal end of the humerus consists of several features: Condyle, consisting of the capitulum and trochlea Medial and lateral epicondyles Medial and lateral supracondylar ridges Radial fossa, coronoid fossa, olecranon fossa A large central condyle which has two articular components – the capitulum which articulates with the radius, and the trochlea which articulates with the ulna. Either side of the humeral condyle, are two epicondyles, the medial and lateral epicondyles superior to which are the medial and lateral supracondylar ridges. There are three fossae found distally …

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radial fossa

Quadratus Lumborum

Quadratus Lumborum The structure indicated is the quadratus lumborum muscle. The quadratus lumborum muscle is one of the muscles which makes up the posterior abdominal wall. There are four muscles which contribute to the posterior abdominal wall: Psoas major Psoas minor Quadratus lumborum Iliacus Origin: Transverse process of L5, iliolumbar ligament, iliac crest. Insertion: Transverse processes of L1-L4, inferior border of 12th rib Action: Depresses and stabilises 12th rib. Weak lateral flexion of trunk Innervation: Anterior rami of T12-L4 Learn more about the muscles of the posterior abdominal wall in this tutorial
quadratus lumborum

Surgical Neck of Humerus

Surgical Neck of Humerus The structure indicated is the surgical neck of the humerus. The proximal end of the humerus consists of the following features: Head Anatomical neck Surgical neck Greater and lesser tubercles Intertubercular sulcus (bicipital groove) Deltoid tuberosity Superior, middle and inferior facets The anatomical neck of the humerus is located distal to the head of the humerus, at an oblique angle to the shaft of the humerus. The surgical neck of the humerus on the other hand is a constriction of the humerus located inferior to the greater and lesser tubercles. It is a clinically important anatomical …

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surgical neck of humerus