System: Musculoskeletal

Sacrotuberous Ligament

Sacrotuberous Ligament The structure indicated is the sacrotuberous ligament. The sacrotuberous ligament runs from the sacrum (sacro-) to the ischial tuberosity (-tuberous). The sacrotuberous ligament contains the coccygeal branch of the inferior gluteal artery. In combination with the sacrospinous ligament, the two ligaments serve to form two important foramina which allow structures to exit the pelvis: Greater sciatic foramen Lesser sciatic foramen The sacrospinous ligament runs from the sacrum and coccyx to the ischial spine. The greater sciatic foramen is formed by the sacrospinous ligament and the greater sciatic notch; the lesser sciatic foramen is formed by the sacrotuberous ligament …

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Sacrotuberous Ligament

Styloid Process of Radius

Styloid Process of Radius The structure indicated in this diagram is the styloid process of the radius. The distal end of the radius consists of: Radial styloid process Two facets for articulation with the scaphoid and lunate bone Ulnar notch The radial styloid process projects obliquely downward from the distal end of the radius. It serves as the point of attachment for the brachioradialis muscle and the radial collateral ligament. Laterally, the tendons of extensor pollicis brevis and abductor pollicis longus run in a flat groove. Chauffeur’s fracture is the name given to fracture of the radial styloid and typically …

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Styloid Process of Radius

Carpal Tunnel

Carpal Tunnel Represented in this diagram is the carpal tunnel. The carpal tunnel is formed by an arch of carpal bones and the flexor retinaculum, found on the anterior aspect of the wrist. The flexor retinaculum attaches on the radial side to the scaphoid tubercle and the trapezium bone; on the ulnar side it attaches to the hook of the hamate and the pisiform. Its attachment over the arch of carpal bones converts the space into a tunnel which allows for the passage of several tendons and the median nerve. The carpal tunnel contains nine long flexor tendons and the …

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Carpal Tunnel

Tibialis Anterior

Tibialis Anterior The muscle highlighted is the tibialis anterior muscle. The tibialis anterior is one of the four muscles of the anterior compartment of the leg. The muscles of the leg consist of three compartments: Anterior Posterior Lateral In the anterior compartment are the four following muscles: Tibialis anterior Extensor hallucis longus Extensor digitorum longus Fibularis tertius The muscles of the anterior compartment of the leg serve to dorsiflex the ankle joint, extend the toes and invert the foot, and they are supplied by the deep fibular (peroneal) nerve. Origin: Upper two-thirds and lateral condyle of the tibia Insertion: Medial …

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Tibialis Anterior

Coccyx

Coccyx The structure indicated is the coccyx. The coccyx forms the terminal aspect of the spinal column, and is comprised of three to five fused vertebrae. In humans and other great apes, the coccyx is the remnant of a vestigial tail. Superiorly, the coccyx articulates with the sacrum. On this superior surface is a facet for articulation with the sacrum, and also two processes which extend superiorly, known as cornua or horns. On the lateral surface of the coccygeal vertebrae are transverse processes – this process is most prominent on the first coccygeal vertebrae. The coccyx contains no spinous processes, …

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Coccyx

Quadratus Plantae Muscle

Quadratus Plantae Muscle The muscle highlighted is the quadratus plantae muscle of the foot. The intrinsic muscles on the plantar aspect of the foot are divided into four layers. The quadratus plantae muscle is found in the second layer of muscles. There are two muscles in the second layer: Quadratus plantae Lumbricals The muscles in the second layer are associated with the tendons of the flexor digitorum longus muscle. This tendon forms the site of insertion for the quadratus plantae muscle, and forms the site of origin for the four lumbricals. The quadratus plantae muscle has two heads – a …

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Quadratus Plantae

Capitate Bone

Capitate Bone The structure highlighted is the capitate bone of the hand. There are three groups of bones in the hand: Carpal bones (8 in total) Metacarpal bones Phalanges The carpal bones are separated into two rows: Proximal row Distal row The capitate bone is located in the distal row of carpal bones. It is the largest of the carpal bones and is located centrally in the wrist. The capitate bone has a “head” which articulates with the scaphoid and lunate bones of the proximal row. Laterally, on the radial side is the trapezoid bone, on medially, on the ulnar side …

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Capitate Bone

Navicular Bone

Navicular Bone The structure highlighted is the navicular bone of the foot. The foot contains three groups of bones: Tarsals Metatarsals Phalanges The navicular is one of seven tarsal bones. There are three groups of tarsal bones: Proximal group Intermediate group Distal group The navicular bone is the only bone in the intermediate group and is located medially in the foot. Posteriorly, the navicular articulates with the talus. Anteriorly, the navicular articulates with the cuneiform bones and laterally it articulates with the cuboid bone. There is only one muscle which attaches to the navicular bone: the tibialis posterior. It attaches onto the tuberosity …

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Navicular

Internal Intercostal Muscle

Internal Intercostal Muscle The structure indicated is the internal intercostal muscle. The intercostal muscles are a set of three flat muscles which are located in each intercostal space. The three intercostal muscles, from superficial to deep are: External intercostal Internal intercostal Innermost intercostal Origin: Lateral edge of costal groove of rib directly above Insertion: Superiorly on rib directly below Innervation: Intercostal nerves (T1 – T11) Action: Forced expiration, movement of ribs inferiorly The muscle fibres of the internal intercostal muscles pass obliquely in the opposite direction to the external intercostal muscles, whose fibres pass anteroinferiorly (when the thoracic wall is viewed …

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Internal Intercostal

Styloglossus Muscle

Styloglossus Muscle The muscle indicated is the styloglossus muscle       . The styloglossus muscles is one of three styloid muscles. The three styloid muscles are: Styloglossus Stylohyoid Stylopharyngeus Origin: Styloid process of temporal bone Insertion: lateral aspect of tongue Innervation: Hypoglossal nerve (cranial nerve 12) Action: Elevation and retraction of the tongue The styloid muscle is one of several extrinsic muscles of the tongue. Learn all about the extrinsic muscle of the tongue in this anatomy tutorial.
Styloglossus