An important bone mark.

Mastoid process: located below the external ear, there is a stem-like mastoid process in front of the front edge of its root, from which the facial nerve exits the skull. The second half of the deep surface of the mastoid is the sigmoid groove.

Mandibular angle: it is the turning point between the posterior edge of mandibular branch and the lower edge of mandibular body, where the bone is thin and easy to fracture.

External occipital protuberance: the most prominent protuberance located in the occipital region, whose deep surface is sinus confluence.

Zygomatic arch: located on the same horizontal plane as the connecting line between the lower orbital margin and the extraoccipital protuberance, and the parotid duct is located at the lower transverse finger.

Wing point: it is the junction of parietal bone, frontal bone, sphenoid bone and temporal bone, 3~4cm above the midpoint of zygomatic arch, which is the weak part of skull, and the anterior branch of middle meningeal artery passes through the groove near its deep surface.

Spinous process of the seventh cervical vertebra: the most prominent protrusion at the back of the neck, which is easy to reach when the head bends forward. It is the symbol of several vertebrae.

Carotid tubercle: the anterior tubercle of the transverse process of the sixth cervical vertebra, located deep in the anterior edge of sternocleidomastoid muscle, facing the cricoid cartilage plane. Flat cricoid cartilage, located at the anterior edge of sternocleidomastoid muscle, can press the common carotid artery to the carotid nodule with the thumb to stop the blood flow and achieve the purpose of hemostasis.

Sternal jugular vein incision: located in the depression of the upper edge of the sternum between the sternoclavicular joints on both sides, with the suprasternal fossa above.

Sternal angle: The joint between the sternum stalk and the sternum body protrudes forward and outward, and is about two fingers downward from the jugular vein notch, which is an important bone sign. The level of the lower edge of the fourth thoracic vertebra is also the level of tracheal bifurcation, anterior and posterior ends of aortic arch, upper margin of heart, second stenosis of esophagus and left displacement of thoracic duct. On both sides of sternal angle is the second costal cartilage, which is a sign of counting ribs. Sternal angle plane is the dividing line between upper and lower mediastinum.

Subscapular angle: when in natural posture, the seventh rib is attached flat, which can be used as the position of several ribs on the back.

Xiphoid process: The process below the sternum is located between the two costal arches, and the intersection of xiphoid process and left costal arch is the common part of pericardiocentesis.

Sacral angle: buckle down to the sacral canal hiatus along the median sacral ridge, and buckle to the sacral angle on both sides of the hiatus.

Acromion: Towering above the shoulder joint, it is the highest point of the shoulder.

Eagle's beak: the protrusion behind time.

Pisiform bone: A protrusion located inside the dermatoglyphics at the distal end of the wrist.

Iliac crest: The entire length of the iliac crest can be buckled on the body surface, with the anterior superior iliac spine at its front end and the posterior superior iliac spine at its rear end. The highest point of iliac spine is parallel to the spinous process of the fourth lumbar vertebra, and lumbar puncture can be located through iliac crest.

Pubic tubercle: located at the inner end of groin, thin people are more conscious than Yikou.

Sciatic tubercle: located on the inner side of the lower edge of gluteus maximus, it is the bony protrusion of the hip when the thigh is bent.

Greater trochanter of femur: lateral protrusion of thigh. During hip flexion, the line from the ischial tubercle to the anterior superior iliac spine passes through the femoral rotor.

Tibial tuberosity: located at the four transverse fingers of the lower edge of patella.

Medial ankle and lateral ankle: The medial ankle and lateral ankle are obviously protruding on both sides of the ankle, and the lateral ankle is lower than the medial ankle. 、

Iliac tubercle

Small tubercle of calcaneus