System: Musculoskeletal

Frontal Bone

Frontal Bone The structure indicated is the frontal bone of the skull The frontal bone is one of 8 bones which form the calvaria (the part of the skull which contains the brain). The calvaria consists of: 2 parietal bones 2 temporal bones Frontal bone Sphenoid bone Ethmoid bone Occipital bone The frontal bone consists of three parts: Squamous part Orbital part Nasal part The frontal bone articulates with the following bones: Sphenoid bones Ethmoid bone Parietal bones Nasal bones Maxillae bones Lacrimal bones Zygomatic bones The point at which the frontal bones meet the parietal bones in the midline …

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frontal bone

Sternal Angle

Sternal Angle The diagram indicates the sternal angle of Louis. The sternal angle is the angle formed between the manubrium of the sternum and the body of the sternum (manubriosternal junction), and is an important anatomical landmark. It marks the level of the 2nd pair of costal cartilages which lies at the level of the intervertebral disc between thoracic vertebrae 4 and 5. This level represents several important anatomical features: Beginning and end of the aortic arch Bifurcation of the trachea Bifurcation of the pulmonary trunk Left recurrent laryngeal loops under arch of aorta Ligamentum arteriosum lies at this level …

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sternal angle

Psoas Major

Psoas Major The structure indicated is the psoas major muscle The psoas major 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 The iliacus muscle combines with the psoas major muscle to enter the anterior compartment of the thigh and insert via a common tendon on the lesser trochanter of the femur. The iliacus and the psoas major muscles are thus collectively referred to as the iliopsoas muscle – they act synergistically to flex the thigh at the …

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psoas major

Pectoralis Minor

Pectoralis Minor The structure indicated is the pectoralis minor muscle. The pectoralis minor muscle lies deep to the much larger, powerful pectoralis major muscle. The pectoralis minor muscle is covered anteriorly by the clavipectoral fascia. This muscle divides the axillary artery into three parts. Part 1 lies proximally to the pectoralis minor, part 2 is the part of the axillary artery covered by the pectoralis minor, and the third part lies distal to the pectoralis minor. The pectoralis minor inserts onto the coracoid process of the scapula. There are three muscles which attach to the coracoid process: Short head of …

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pectoralis minor

Anconeus

Anconeus The structure indicated is the anconeus muscle of the forearm. The anconeus muscle is one of the muscles of the posterior compartment of the forearm. The posterior compartment consists of a superficial layer of muscles comprised of 7 muscles. The deep layer is comprised of 5 muscles. Origin: lateral epicondyle of humerus Insertion: olecranon, proximal surface of ulna Innervation: Radial nerve Action: assists elbow extension, stabilises the elbow joint, abducts ulna during pronation Learn about the muscles of the forearm in this tutorial.
anconeus

Flexor Digitorum Brevis

Flexor Digitorum Brevis The structure indicated is the flexor digitorum brevis muscle of the foot. The intrinsic muscles on the plantar aspect of the foot are divided into four layers. The flexor digitorum brevis muscles is found in the first layer of muscles. There are three muscles in the first layer: Abductor hallucis Flexor digitorum brevis Abductor digiti minimi The flexor digitorum brevis muscle lies above the  central part of the plantar aponeurosis and just below the tendons of flexor digitorum longus. Origin: medial process of calcaneal tuberosity and plantar aponeurosis. Insertion: Plantar sides of middle phalanges of lateral four …

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flexor digitorum brevis

Xiphoid Process

Xiphoid Process The highlighted structure is the xiphoid process of the sternum. The sternum consists of three parts: Manubrium of the sternum Body of sternum Xiphoid process The xiphoid process is the most inferior part of the sternum and is the smallest part. Learn more about the sternum in this tutorial!
xiphoid process

Brachioradialis

Brachioradialis The structure indicated is the brachioradialis muscle of the forearm. The brachioradalis muscle is one of the muscles of the posterior compartment of the forearm. The posterior compartment consists of a superficial layer of muscles comprised of 7 muscles. The deep layer is comprised of 5 muscles. Origin: lateral supracondylar ridge of humerus Insertion: radial styloid process Innervation: radial nerve Action: flexes the forearm at the elbow – strongest when forearm is midway between pronation and supination. Learn more about the muscles of the forearm in this tutorial.
brachioradialis

Parietal Bone

Parietal Bone The structure indicated is the parietal bone of the skull. The parietal bone is one of 8 bones which form the calvaria (the part of the skull which contains the brain). The calvaria consists of: 2 parietal bones 2 temporal bones Frontal bone Sphenoid bone Ethmoid bone Occipital bone The parietal bone articulates anteriorly with the frontal bone at the coronal suture. Inferiorly it articulates with the temporal bone at the squamous suture. Posteriorly it articulates with the occipital bone via the lamboid suture. It has a small articulation with the sphenoid bone via the sphenoparietal suture at …

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parietal bone

Serratus Anterior

Serratus Anterior The structure indicated is the serratus anterior muscle. The serratus anterior muscle originates on the first to eighth ribs laterally on the chest and inserts medially on the scapula. The serratus anterior is divided into three parts: Serratus anterior superior Serratus anterior intermediate Serratus anterior inferior The serratus anterior is often called the “boxer’s muscle” as it is responsible for protraction of the scapula – a movement which occurs when throwing a punch. Origin: fleshy slips from lateral parts of 1st to 8th ribs Insertion: Medial margin of scapula on anterior surface Innervation: Long thoracic nerve Action: Protraction …

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Serratus Anterior